2001 Chevy Impala OBD2 Codes: A Comprehensive Troubleshooting Guide

Navigating car troubles can be frustrating, especially when the check engine light illuminates in your 2001 Chevy Impala. Fortunately, modern vehicles like the 2001 Chevy Impala are equipped with an On-Board Diagnostics system, specifically OBD2, which helps pinpoint potential issues. This system uses a standardized set of Diagnostic Trouble Codes (DTCs), commonly known as OBD2 codes, to signal problems within your vehicle.

This comprehensive guide is designed to be your go-to resource for understanding 2001 Chevy Impala Obd2 Codes. We’ll delve into what these codes mean, helping you move beyond just seeing a cryptic error message and towards effective car maintenance and repair.

Understanding OBD2 Codes for Your 2001 Chevy Impala

OBD2 (On-Board Diagnostics II) is a standardized system implemented in vehicles sold in the United States from 1996 onwards, including your 2001 Chevy Impala. Its primary function is to monitor the performance of your engine and emissions control systems. When the system detects a problem outside of normal parameters, it triggers the check engine light and stores a corresponding DTC.

These codes are invaluable for mechanics and car owners alike. They provide a starting point for diagnosing issues, saving time and potentially money on repairs. While an OBD2 code can indicate a general area of concern, further investigation is usually needed to pinpoint the exact cause of the problem.

Think of OBD2 codes as symptoms your car is displaying. Just like a doctor uses symptoms to diagnose an illness, a mechanic uses OBD2 codes to diagnose car problems. Understanding these codes is the first step in getting your 2001 Chevy Impala back in top shape.

Decoding 2001 Chevy Impala OBD2 Codes: The P0000 Series

The P0000 range of OBD2 codes generally points to issues within the fuel and air metering system. These systems are crucial for your 2001 Chevy Impala’s engine to run efficiently and cleanly. Problems here can lead to reduced fuel economy, poor engine performance, and increased emissions.

P0001 – P0004: Fuel Volume Regulator Control Circuit Issues

These codes (P0001, P0002, P0003, P0004) relate to the Fuel Volume Regulator Control Circuit. This circuit is responsible for controlling the amount of fuel delivered to your engine. Problems can stem from wiring issues, a faulty fuel volume regulator, or PCM (Powertrain Control Module) malfunctions.

• P0001 Fuel Volume Regulator Control Circuit / Open: Indicates an open circuit, meaning there’s a break in the electrical connection.
• P0002 Fuel Volume Regulator Control Circuit Range/Performance: Suggests the circuit is functioning outside of its expected parameters.
• P0003 Fuel Volume Regulator Control Circuit Low: Signals a low voltage condition in the control circuit.
• P0004 Fuel Volume Regulator Control Circuit High: Indicates a high voltage condition in the control circuit.

P0005 – P0007: Fuel Shutoff Valve A Control Circuit Problems

These codes (P0005, P0006, P0007) focus on the Fuel Shutoff Valve A Control Circuit. This valve is designed to stop fuel flow, often as a safety measure. Issues here can prevent the engine from starting or cause it to stall.

• P0005 Fuel Shutoff Valve A Control Circuit / Open: Points to an open circuit in the fuel shutoff valve control.
• P0006 Fuel Shutoff Valve A Control Circuit Low: Indicates a low voltage issue in the control circuit.
• P0007 Fuel Shutoff Valve A Control Circuit High: Signifies a high voltage problem in the control circuit.

P0008 & P0009: Engine Position System Performance

Codes P0008 and P0009 relate to the Engine Position System Performance, crucial for engine timing and overall function.

• P0008 Engine Position System Performance – Bank 1: Indicates a performance issue with the engine position system on Bank 1 (side of the engine with cylinder #1).
• P0009 Engine Position System Performance – Bank 2: Signals a performance issue with the engine position system on Bank 2 (opposite side of Bank 1, if applicable).

P0010 – P0025: Camshaft Position Actuator Circuit & Timing

This extensive range (P0010 to P0025) deals with the Camshaft Position Actuator Circuit and Timing. These systems are vital for variable valve timing (VVT), which optimizes engine performance and efficiency. Your 2001 Chevy Impala may or may not have VVT depending on the engine option.

• P0010 Intake Camshaft Position Actuator Circuit / Open (Bank 1): An open circuit in the intake camshaft actuator on Bank 1.
• P0011 Intake Camshaft Position Timing – Over-Advanced (Bank 1): The intake camshaft timing is more advanced than commanded on Bank 1.
• P0012 Intake Camshaft Position Timing – Over-Retarded (Bank 1): The intake camshaft timing is more retarded than commanded on Bank 1.
• P0013 Exhaust Camshaft Position Actuator Circuit / Open (Bank 1): An open circuit in the exhaust camshaft actuator on Bank 1.
• P0014 Exhaust Camshaft Position Timing – Over-Advanced (Bank 1): The exhaust camshaft timing is more advanced than commanded on Bank 1.
• P0015 Exhaust Camshaft Position Timing – Over-Retarded (Bank 1): The exhaust camshaft timing is more retarded than commanded on Bank 1.
• P0016 Crankshaft Position – Camshaft Position Correlation – Bank 1 Sensor A: Indicates a mismatch in the correlation between the crankshaft and camshaft position sensors on Bank 1, Sensor A. This can be a serious issue potentially related to timing chain/belt problems.
• P0017 Crankshaft Position – Camshaft Position Correlation – Bank 1 Sensor B: Similar to P0016 but for Sensor B.
• P0018 Crankshaft Position – Camshaft Position Correlation – Bank 2 Sensor A: Correlation issue on Bank 2, Sensor A.
• P0019 Crankshaft Position – Camshaft Position Correlation – Bank 2 Sensor B: Correlation issue on Bank 2, Sensor B.
• P0020 Intake Camshaft Position Actuator Circuit / Open (Bank 2): Open circuit for intake camshaft actuator on Bank 2.
• P0021 Intake Camshaft Position Timing – Over-Advanced (Bank 2): Over-advanced timing on Bank 2 intake camshaft.
• P0022 Intake Camshaft Position Timing – Over-Retarded (Bank 2): Over-retarded timing on Bank 2 intake camshaft.
• P0023 Exhaust Camshaft Position Actuator Circuit / Open (Bank 2): Open circuit for exhaust camshaft actuator on Bank 2.
• P0024 Exhaust Camshaft Position Timing – Over-Advanced (Bank 2): Over-advanced timing on Bank 2 exhaust camshaft.
• P0025 Exhaust Camshaft Position Timing – Over-Retarded (Bank 2): Over-retarded timing on Bank 2 exhaust camshaft.

P0026 – P0029: Valve Control Solenoid Circuit Range/Performance

Codes P0026 through P0029 are concerned with the Valve Control Solenoid Circuit Range/Performance, impacting valve operation and potentially engine efficiency.

• P0026 Intake Valve Control Solenoid Circuit Range/Performance (Bank 1): Performance issue with the intake valve control solenoid on Bank 1.
• P0027 Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 1): Performance issue with the exhaust valve control solenoid on Bank 1.
• P0028 Intake Valve Control Solenoid Circuit Range/Performance (Bank 2): Performance issue with the intake valve control solenoid on Bank 2.
• P0029 Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 2): Performance issue with the exhaust valve control solenoid on Bank 2.

P0030 – P0064: Heated Oxygen Sensor (HO2S) and Turbo/Supercharger Bypass Valve Circuits

This section (P0030 – P0064) covers a range of issues primarily related to Heated Oxygen Sensors (HO2S) and Turbo/Supercharger Bypass Valve Circuits. The 2001 Chevy Impala is not typically turbocharged or supercharged, so codes in the P0033-P0035, P0039, and P0045-P0049 ranges might be less relevant unless modifications have been made. HO2S sensors are critical for emissions control and fuel efficiency.

• P0030 HO2S Heater Control Circuit (Bank 1, Sensor 1): General issue with the heater control circuit for HO2S sensor 1 on Bank 1.
• P0031 HO2S Heater Control Circuit Low (Bank 1, Sensor 1): Low voltage in the heater control circuit for Bank 1, Sensor 1.
• P0032 HO2S Heater Control Circuit High (Bank 1, Sensor 1): High voltage in the heater control circuit for Bank 1, Sensor 1.
• P0033 Turbo/Super Charger Bypass Valve Control Circuit / Open: Open circuit in the turbo/supercharger bypass valve control. (Less relevant for a stock 2001 Impala)
• P0034 Turbo/Super Charger Bypass Valve Control Circuit Low: Low voltage in the bypass valve control. (Less relevant for a stock 2001 Impala)
• P0035 Turbo/Super Charger Bypass Valve Control Circuit High: High voltage in the bypass valve control. (Less relevant for a stock 2001 Impala)
• P0036 HO2S Heater Control Circuit (Bank 1, Sensor 2): Heater control circuit issue for Bank 1, Sensor 2.
• P0037 HO2S Heater Control Circuit Low (Bank 1, Sensor 2): Low voltage for Bank 1, Sensor 2 heater.
• P0038 HO2S Heater Control Circuit High (Bank 1, Sensor 2): High voltage for Bank 1, Sensor 2 heater.
• P0039 Turbo/Super Charger Bypass Valve Control Circuit Range/Performance: Performance issue with bypass valve circuit. (Less relevant for a stock 2001 Impala)
• P0040 Oxygen Sensor Signals Swapped Bank 1 Sensor 1 / Bank 2 Sensor 1: Oxygen sensor signals are incorrectly swapped between Bank 1 Sensor 1 and Bank 2 Sensor 1.
• P0041 Oxygen Sensor Signals Swapped Bank 1 Sensor 2 / Bank 2 Sensor 2: Oxygen sensor signals swapped between Bank 1 Sensor 2 and Bank 2 Sensor 2.
• P0042 HO2S Heater Control Circuit (Bank 1, Sensor 3): Heater circuit issue for Bank 1, Sensor 3 (if applicable – some vehicles may not have sensor 3).
• P0043 HO2S Heater Control Circuit Low (Bank 1, Sensor 3): Low voltage for Bank 1, Sensor 3 heater.
• P0044 HO2S Heater Control Circuit High (Bank 1, Sensor 3): High voltage for Bank 1, Sensor 3 heater.
• P0045 Turbo/Super Charger Boost Control Solenoid Circuit / Open: Open circuit in boost control solenoid. (Less relevant for a stock 2001 Impala)
• P0046 Turbo/Super Charger Boost Control Solenoid Circuit Range/Performance: Performance issue with boost control solenoid. (Less relevant for a stock 2001 Impala)
• P0047 Turbo/Super Charger Boost Control Solenoid Circuit Low: Low voltage in boost control solenoid. (Less relevant for a stock 2001 Impala)
• P0048 Turbo/Super Charger Boost Control Solenoid Circuit High: High voltage in boost control solenoid. (Less relevant for a stock 2001 Impala)
• P0049 Turbo/Super Charger Turbine Overspeed: Turbine speed is too high. (Less relevant for a stock 2001 Impala)
• P0050 HO2S Heater Control Circuit (Bank 2, Sensor 1): Heater control circuit issue for Bank 2, Sensor 1.
• P0051 HO2S Heater Control Circuit Low (Bank 2, Sensor 1): Low voltage for Bank 2, Sensor 1 heater.
• P0052 HO2S Heater Control Circuit High (Bank 2, Sensor 1): High voltage for Bank 2, Sensor 1 heater.
• P0053 HO2S Heater Resistance (Bank 1, Sensor 1): Heater resistance is outside of specification for Bank 1, Sensor 1.
• P0054 HO2S Heater Resistance (Bank 1, Sensor 2): Heater resistance issue for Bank 1, Sensor 2.
• P0055 HO2S Heater Resistance (Bank 1, Sensor 3): Heater resistance issue for Bank 1, Sensor 3.
• P0056 HO2S Heater Control Circuit (Bank 2, Sensor 2): Heater control circuit issue for Bank 2, Sensor 2.
• P0057 HO2S Heater Control Circuit Low (Bank 2, Sensor 2): Low voltage for Bank 2, Sensor 2 heater.
• P0058 HO2S Heater Control Circuit High (Bank 2, Sensor 2): High voltage for Bank 2, Sensor 2 heater.
• P0059 HO2S Heater Resistance (Bank 2, Sensor 1): Heater resistance issue for Bank 2, Sensor 1.
• P0060 HO2S Heater Resistance (Bank 2, Sensor 2): Heater resistance issue for Bank 2, Sensor 2.
• P0061 HO2S Heater Resistance (Bank 2, Sensor 3): Heater resistance issue for Bank 2, Sensor 3.
• P0062 HO2S Heater Control Circuit (Bank 2, Sensor 3): Heater control circuit issue for Bank 2, Sensor 3.
• P0063 HO2S Heater Control Circuit Low (Bank 2, Sensor 3): Low voltage for Bank 2, Sensor 3 heater.
• P0064 HO2S Heater Control Circuit High (Bank 2, Sensor 3): High voltage for Bank 2, Sensor 3 heater.

P0065 – P0099: Air Assisted Injector Control & Fuel Pressure Issues

Codes P0065 through P0099 cover a range of issues, from Air Assisted Injector Control to Fuel Pressure Regulator problems. These systems are all related to ensuring the correct air/fuel mixture for optimal combustion. Air assisted injectors are less common in standard passenger vehicles, so codes related to these (P0065-P0067) might be less frequent in a 2001 Impala unless it has specific aftermarket systems.

• P0065 Air Assisted Injector Control Range/Performance: Performance issue with air assisted injector control. (Less common in 2001 Impala)
• P0066 Air Assisted Injector Control Circuit or Circuit Low: Circuit issue or low voltage for air assisted injectors. (Less common in 2001 Impala)
• P0067 Air Assisted Injector Control Circuit High: High voltage in air assisted injector circuit. (Less common in 2001 Impala)
• P0068 MAP / MAF – Throttle Position Correlation: Mismatch in readings between Manifold Absolute Pressure (MAP) or Mass Air Flow (MAF) sensor and Throttle Position Sensor (TPS).
• P0069 MAP – Barometric Pressure Correlation: Mismatch between MAP sensor reading and Barometric Pressure.
• P0070 Ambient Air Temperature Sensor Circuit: Circuit issue with the ambient air temperature sensor.
• P0071 Ambient Air Temperature Sensor Range/Performance: Ambient air temperature sensor reading is out of range.
• P0072 Ambient Air Temperature Sensor Circuit Low Input: Low input signal from the ambient air temperature sensor.
• P0073 Ambient Air Temperature Sensor Circuit High Input: High input signal from the ambient air temperature sensor.
• P0074 Ambient Air Temperature Sensor Circuit Intermittent/Erratic: Intermittent or erratic signal from the ambient air temperature sensor.
• P0075 Intake Valve Control Circuit (Bank 1): Circuit issue with the intake valve control on Bank 1.
• P0076 Intake Valve Control Circuit Low (Bank 1): Low voltage in intake valve control circuit on Bank 1.
• P0077 Intake Valve Control Circuit High (Bank 1): High voltage in intake valve control circuit on Bank 1.
• P0078 Exhaust Valve Control Circuit (Bank 1): Circuit issue for exhaust valve control on Bank 1.
• P0079 Exhaust Valve Control Circuit Low (Bank 1): Low voltage in exhaust valve control on Bank 1.
• P0080 Exhaust Valve Control Circuit High (Bank 1): High voltage in exhaust valve control on Bank 1.
• P0081 Intake Valve Control Circuit (Bank 2): Circuit issue for intake valve control on Bank 2.
• P0082 Intake Valve Control Circuit Low (Bank 2): Low voltage in intake valve control on Bank 2.
• P0083 Intake Valve Control Circuit High (Bank 2): High voltage in intake valve control on Bank 2.
• P0084 Exhaust Valve Control Circuit (Bank 2): Circuit issue for exhaust valve control on Bank 2.
• P0085 Exhaust Valve Control Circuit Low (Bank 2): Low voltage in exhaust valve control on Bank 2.
• P0086 Exhaust Valve Control Circuit High (Bank 2): High voltage in exhaust valve control on Bank 2.
• P0087 Fuel Rail/System Pressure – Too Low: Fuel pressure in the fuel rail is too low.
• P0088 Fuel Rail/System Pressure – Too High: Fuel pressure in the fuel rail is too high.
• P0089 Fuel Pressure Regulator Performance: Performance issue with the fuel pressure regulator.
• P0090 Fuel Pressure Regulator Control Circuit: Circuit issue with the fuel pressure regulator control.
• P0091 Fuel Pressure Regulator Control Circuit Low: Low voltage in fuel pressure regulator control circuit.
• P0092 Fuel Pressure Regulator Control Circuit High: High voltage in fuel pressure regulator control circuit.
• P0093 Fuel System Leak Detected – Large Leak: Large fuel leak detected in the fuel system.
• P0094 Fuel System Leak Detected – Small Leak: Small fuel leak detected in the fuel system.
• P0095 Intake Air Temperature Sensor 2 Circuit: Circuit issue with intake air temperature sensor 2.
• P0096 Intake Air Temperature Sensor 2 Circuit Range/Performance: Intake air temperature sensor 2 reading out of range.
• P0097 Intake Air Temperature Sensor 2 Circuit Low Input: Low input signal from intake air temperature sensor 2.
• P0098 Intake Air Temperature Sensor 2 Circuit High Input: High input signal from intake air temperature sensor 2.
• P0099 Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic: Intermittent or erratic signal from intake air temperature sensor 2.

Decoding 2001 Chevy Impala OBD2 Codes: The P0100 Series

The P0100 series of OBD2 codes expands on the fuel and air system, and also delves into ignition and misfire detection. These codes are crucial for maintaining engine performance, fuel efficiency, and emissions control in your 2001 Chevy Impala.

P0100 – P0104: Mass or Volume Air Flow Circuit Issues

These codes (P0100, P0101, P0102, P0103, P0104) point to problems with the Mass Air Flow (MAF) or Volume Air Flow (VAF) sensor circuit. The MAF sensor measures the amount of air entering the engine, which is critical for the PCM to calculate the correct fuel mixture.

• P0100 Mass or Volume Air Flow Circuit: General circuit malfunction in the MAF or VAF sensor circuit.
• P0101 Mass or Volume Air Flow Circuit Range/Performance: MAF or VAF sensor reading is out of the expected range.
• P0102 Mass or Volume Air Flow Circuit Low Input: Low voltage signal from the MAF or VAF sensor, often indicating a low airflow reading when there should be more.
• P0103 Mass or Volume Air Flow Circuit High Input: High voltage signal, possibly suggesting a high airflow reading when it’s not actually that high.
• P0104 Mass or Volume Air Flow Circuit Intermittent: Intermittent signal from the MAF or VAF sensor, meaning the signal is fluctuating unexpectedly.

P0105 – P0109: Manifold Absolute Pressure/BARO Circuit Issues

Codes P0105 through P0109 relate to the Manifold Absolute Pressure (MAP) or BARO (Barometric Pressure) sensor circuit. The MAP sensor measures the pressure in the intake manifold, while the BARO sensor measures atmospheric pressure. Both are important for air density calculations and engine management.

• P0105 Manifold Absolute Pressure/BARO Circuit: General circuit malfunction in the MAP/BARO sensor circuit.
• P0106 Manifold Absolute Pressure/BARO Sensor Range/Performance: MAP/BARO sensor reading is outside the expected range.
• P0107 Manifold Absolute Pressure/BARO Sensor Low Input: Low voltage signal from the MAP/BARO sensor, indicating low pressure.
• P0108 Manifold Absolute Pressure/BARO Sensor High Input: High voltage signal, suggesting high pressure.
• P0109 Manifold Absolute Pressure/BARO Sensor Intermittent: Intermittent signal from the MAP/BARO sensor.

P0110 – P0114: Intake Air Temperature Sensor 1 Circuit Issues

This range (P0110 to P0114) is focused on the Intake Air Temperature (IAT) Sensor 1 circuit. The IAT sensor measures the temperature of the air entering the engine, which influences air density and fuel mixture calculations.

• P0110 Intake Air Temperature Sensor 1 Circuit: General circuit malfunction in the IAT sensor 1 circuit.
• P0111 Intake Air Temperature Sensor 1 Circuit Range/Performance: IAT sensor 1 reading is out of the expected range.
• P0112 Intake Air Temperature Sensor 1 Circuit Low Input: Low voltage signal from IAT sensor 1, suggesting a low temperature reading.
• P0113 Intake Air Temperature Sensor 1 Circuit High Input: High voltage signal, potentially indicating a high-temperature reading.
• P0114 Intake Air Temperature Sensor 1 Intermittent/Erratic: Intermittent signal from IAT sensor 1.

P0115 – P0119: Engine Coolant Temperature Circuit Issues

Codes P0115 through P0119 relate to the Engine Coolant Temperature (ECT) circuit. The ECT sensor monitors the engine coolant temperature, which is critical for engine management, temperature gauge readings, and preventing overheating.

• P0115 Engine Coolant Temperature Circuit: General circuit malfunction in the ECT sensor circuit.
• P0116 Engine Coolant Temperature Circuit Range/Performance: ECT sensor reading is out of the expected range.
• P0117 Engine Coolant Temperature Circuit Low Input: Low voltage signal from the ECT sensor, indicating a low-temperature reading (engine might appear colder than it is).
• P0118 Engine Coolant Temperature Circuit High Input: High voltage signal, possibly suggesting a high-temperature reading (engine might appear hotter than it is).
• P0119 Engine Coolant Temperature Circuit Intermittent: Intermittent signal from the ECT sensor.

P0120 – P0124: Throttle/Pedal Position Sensor A Circuit Issues

This range (P0120 to P0124) covers the Throttle/Pedal Position Sensor A circuit. The Throttle Position Sensor (TPS) measures the position of the throttle plate, indicating how much the driver is pressing the accelerator pedal. This is crucial for controlling engine power.

• P0120 Throttle/Pedal Position Sensor A Circuit: General circuit malfunction in TPS A circuit.
• P0121 Throttle/Pedal Position Sensor A Circuit Range/Performance: TPS A reading is out of the expected range.
• P0122 Throttle/Pedal Position Sensor A Circuit Low Input: Low voltage signal from TPS A, suggesting a closed throttle position when it might be open.
• P0123 Throttle/Pedal Position Sensor A Circuit High Input: High voltage signal, potentially indicating an open throttle position when it’s closed.
• P0124 Throttle/Pedal Position Sensor A Intermittent: Intermittent signal from TPS A.

P0125 – P0129: Coolant Temperature and Barometric Pressure Issues (Performance)

Codes P0125 through P0129 address performance issues related to coolant temperature, intake air temperature, and barometric pressure.

• P0125 Insufficient Coolant Temp For Closed Loop Fuel Control: Engine coolant is not reaching the required temperature for the system to enter closed-loop fuel control (optimized emissions and fuel efficiency).
• P0126 Insufficient Coolant Temp For Stable Operation: Coolant temperature is too low for stable engine operation.
• P0127 Intake Air Temperature Too High: Intake air temperature is excessively high.
• P0128 Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature): The coolant temperature is below the thermostat’s regulating temperature, often indicating a stuck-open thermostat.
• P0129 Barometric Pressure Too Low: Barometric pressure reading is abnormally low.

P0130 – P0167: Oxygen Sensor Circuit Issues (Bank 1 & 2, Sensors 1, 2, & 3)

This large section (P0130 to P0167) is dedicated to Oxygen Sensor (O2) circuit issues, specifically for Bank 1 and Bank 2, and Sensors 1, 2, and 3. Oxygen sensors measure the oxygen content in the exhaust, providing feedback to the PCM to adjust the air/fuel mixture for optimal combustion and emissions.

• P0130 O2 Circuit (Bank 1, Sensor 1): General circuit malfunction for Bank 1, Sensor 1 O2 sensor.
• P0131 O2 Circuit Low Voltage (Bank 1, Sensor 1): Low voltage signal from Bank 1, Sensor 1 O2 sensor, often indicating a lean condition (too much oxygen in the exhaust).
• P0132 O2 Circuit High Voltage (Bank 1, Sensor 1): High voltage signal, suggesting a rich condition (too little oxygen).
• P0133 O2 Circuit Slow Response (Bank 1, Sensor 1): Slow response from Bank 1, Sensor 1 O2 sensor.
• P0134 O2 Circuit No Activity Detected (Bank 1, Sensor 1): No signal or activity from Bank 1, Sensor 1.
• P0135 O2 Heater Circuit (Bank 1, Sensor 1): Heater circuit issue for Bank 1, Sensor 1 O2 sensor.
• P0136 O2 Circuit (Bank 1, Sensor 2): General circuit issue for Bank 1, Sensor 2.
• P0137 O2 Circuit Low Voltage (Bank 1, Sensor 2): Low voltage from Bank 1, Sensor 2.
• P0138 O2 Circuit High Voltage (Bank 1, Sensor 2): High voltage from Bank 1, Sensor 2.
• P0139 O2 Circuit Slow Response (Bank 1, Sensor 2): Slow response from Bank 1, Sensor 2.
• P0140 O2 Circuit No Activity Detected (Bank 1, Sensor 2): No activity from Bank 1, Sensor 2.
• P0141 O2 Heater Circuit (Bank 1, Sensor 2): Heater circuit issue for Bank 1, Sensor 2.
• P0142 O2 Circuit (Bank 1, Sensor 3): General circuit issue for Bank 1, Sensor 3 (if applicable).
• P0143 O2 Circuit Low Voltage (Bank 1, Sensor 3): Low voltage from Bank 1, Sensor 3.
• P0144 O2 Circuit High Voltage (Bank 1, Sensor 3): High voltage from Bank 1, Sensor 3.
• P0145 O2 Circuit Slow Response (Bank 1, Sensor 3): Slow response from Bank 1, Sensor 3.
• P0146 O2 Circuit No Activity Detected (Bank 1, Sensor 3): No activity from Bank 1, Sensor 3.
• P0147 O2 Heater Circuit (Bank 1, Sensor 3): Heater circuit issue for Bank 1, Sensor 3.
• (P0148 Fuel Delivery Error & P0149 Fuel Timing Error): These codes indicate general errors with fuel delivery (P0148) or fuel timing (P0149). These are broader codes and require further investigation.
• (P0150 – P0167): These codes mirror P0130-P0147 but are for Bank 2, Sensors 1, 2, and 3. They indicate the same types of circuit, voltage, response, and heater issues but on the opposite bank of the engine (Bank 2).

P0168 – P0199: Fuel Temperature, Composition, and Pressure Issues

The final part of the P0100 series (P0168 to P0199) covers problems related to fuel temperature, fuel composition, and fuel rail pressure.

• P0168 Engine Fuel Temperature Too High: Fuel temperature is excessively high.
• P0169 Incorrect Fuel Composition: Fuel composition is not within expected parameters (relevant for flex-fuel vehicles, less likely on a standard 2001 Impala unless there’s contamination).
• P0170 Fuel Trim (Bank 1): General fuel trim issue on Bank 1. Fuel trim refers to the PCM’s adjustments to the air/fuel mixture to maintain stoichiometry.
• P0171 System Too Lean (Bank 1): Fuel system is running too lean on Bank 1 (too much air, not enough fuel).
• P0172 System Too Rich (Bank 1): Fuel system is running too rich on Bank 1 (too much fuel, not enough air).
• P0173 Fuel Trim (Bank 2): General fuel trim issue on Bank 2.
• P0174 System Too Lean (Bank 2): Fuel system too lean on Bank 2.
• P0175 System Too Rich (Bank 2): Fuel system too rich on Bank 2.
• P0176 Flexible Fuel Sensor Circuit: Circuit issue with the flexible fuel sensor (flex-fuel vehicles).
• P0177 Flexible Fuel Sensor Circuit Range/Performance: Performance issue with flex-fuel sensor.
• P0178 Flexible Fuel Sensor Circuit Low Input: Low input from flex-fuel sensor.
• P0179 Flexible Fuel Sensor Circuit High Input: High input from flex-fuel sensor.
• P0180 Fuel Temperature Sensor A Circuit: Circuit issue with Fuel Temperature Sensor A.
• P0181 Fuel Temperature Sensor A Circuit Range/Performance: Performance issue with Fuel Temperature Sensor A.
• P0182 Fuel Temperature Sensor A Circuit Low Input: Low input from Fuel Temperature Sensor A.
• P0183 Fuel Temperature Sensor A Circuit High Input: High input from Fuel Temperature Sensor A.
• P0184 Fuel Temperature Sensor A Circuit Intermittent: Intermittent signal from Fuel Temperature Sensor A.
• (P0185 – P0189): These codes mirror P0180-P0184 but are for Fuel Temperature Sensor B, if equipped.
• P0190 Fuel Rail Pressure Sensor: Circuit issue with the fuel rail pressure sensor.
• P0191 Fuel Rail Pressure Sensor Range/Performance: Fuel rail pressure sensor reading out of range.
• P0192 Fuel Rail Pressure Sensor Low Input: Low input from fuel rail pressure sensor, indicating low pressure.
• P0193 Fuel Rail Pressure Sensor High Input: High input, suggesting high pressure.
• P0194 Fuel Rail Pressure Sensor Intermittent: Intermittent signal from fuel rail pressure sensor.
• P0195 Engine Oil Temperature Sensor Circuit: Circuit issue with the engine oil temperature sensor.
• P0196 Engine Oil Temperature Sensor Circuit Range/Performance: Performance issue with engine oil temperature sensor.
• P0197 Engine Oil Temperature Sensor Circuit Low Input: Low input from engine oil temperature sensor, suggesting low oil temperature (or sensor fault).
• P0198 Engine Oil Temperature Sensor Circuit High Input: High input, suggesting high oil temperature.
• P0199 Engine Oil Temperature Sensor Circuit Intermittent: Intermittent signal from engine oil temperature sensor.

Decoding 2001 Chevy Impala OBD2 Codes: The P0200 Series

The P0200 series OBD2 codes for your 2001 Chevy Impala primarily focus on injector circuit malfunctions and misfires. Fuel injectors are responsible for delivering precise amounts of fuel into the engine cylinders. Issues in this area directly impact engine performance, fuel economy, and emissions.

P0200 – P0212: Injector Circuit Issues (Cylinders 1-12)

This extensive range (P0200 to P0212) deals with injector circuit problems, specifically for individual cylinders. Your 2001 Chevy Impala will have either a V6 or V8 engine, so codes up to P0206 (for V6) or P0208 (for common V8s) are most relevant. Codes beyond P0208 are for engines with more cylinders, which the standard 2001 Impala does not have.

• P0200 Injector Circuit: General malfunction in the injector circuit. This code indicates a problem affecting the overall injector system, not necessarily a specific cylinder.
• P0201 Injector Circuit / Open – Cylinder 1: Open circuit (break in electrical connection) in the injector circuit for cylinder 1. This means cylinder 1’s injector is likely not firing.
• P0202 Injector Circuit / Open – Cylinder 2: Open circuit for cylinder 2 injector.
• P0203 Injector Circuit / Open – Cylinder 3: Open circuit for cylinder 3 injector.
• P0204 Injector Circuit / Open – Cylinder 4: Open circuit for cylinder 4 injector.
• P0205 Injector Circuit / Open – Cylinder 5: Open circuit for cylinder 5 injector.
• P0206 Injector Circuit / Open – Cylinder 6: Open circuit for cylinder 6 injector.
• (P0207 – P0212): These codes continue the pattern for cylinders 7 through 12, indicating open circuits in their respective injector circuits. Less relevant for a standard 2001 Impala engine.

P0213 & P0214: Cold Start Injector Issues

Codes P0213 and P0214 pertain to Cold Start Injectors. These injectors, if equipped (less common in modern vehicles), provide extra fuel during cold starts to improve engine starting in cold conditions.

• P0213 Cold Start Injector 1: Malfunction in cold start injector 1 circuit.
• P0214 Cold Start Injector 2: Malfunction in cold start injector 2 circuit (if equipped).

P0215 – P0219: Engine Shutoff, Injection Timing, and Overspeed Issues

This section (P0215 – P0219) covers a range of engine-related issues, including engine shutoff solenoid problems, injection timing control, and engine overspeed conditions.

• P0215 Engine Shutoff Solenoid: Malfunction in the engine shutoff solenoid circuit. This solenoid is designed to cut off fuel to stop the engine.
• P0216 Injector/Injection Timing Control Circuit: Malfunction in the injector or injection timing control circuit. This is a broad code suggesting problems with the system that controls when and how fuel is injected.
• P0217 Engine Coolant Overtemperature Condition: Engine coolant temperature is excessively high, indicating overheating. This is a serious condition that can cause engine damage.
• P0218 Transmission Fluid Overtemperature Condition: Transmission fluid temperature is too high, potentially leading to transmission damage.
• P0219 Engine Overspeed Condition: Engine speed (RPM) has exceeded the safe limit, which can damage the engine.

P0220 – P0229: Throttle/Pedal Position Switch B & C Circuit Issues

Codes P0220 through P0229 focus on Throttle/Pedal Position Switch B and C circuits. These are related to the accelerator pedal and throttle position, providing redundant signals to the PCM for throttle control and safety.

• P0220 Throttle/Pedal Position Switch B Circuit: General malfunction in Throttle/Pedal Position Switch B circuit.
• P0221 Throttle/Pedal Position Switch B Circuit Range/Performance: Performance issue with Switch B circuit.
• P0222 Throttle/Pedal Position Sensor B Circuit Low Input: Low input signal from Throttle/Pedal Position Sensor B.
• P0223 Throttle/Pedal Position Sensor B Circuit High Input: High input signal from Sensor B.
• P0224 Throttle/Pedal Position Sensor B Circuit Intermittent: Intermittent signal from Sensor B.
• (P0225 – P0229): These codes mirror P0220-P0224 but are for Throttle/Pedal Position Sensor C circuit, indicating similar circuit malfunctions, range/performance issues, and signal problems but related to Sensor C.

P0230 – P0250: Fuel Pump and Turbo/Supercharger Wastegate Issues

This section (P0230 – P0250) covers fuel pump circuit problems and Turbo/Supercharger Wastegate Solenoid issues. Again, for a stock 2001 Chevy Impala, the turbo/supercharger related codes (P0234-P0250) are less likely to be relevant unless aftermarket modifications are present.

• P0230 Fuel Pump Primary Circuit: Malfunction in the fuel pump primary circuit. This is the main power circuit for the fuel pump.
• P0231 Fuel Pump Secondary Circuit Low: Low voltage in the fuel pump secondary circuit (control circuit).
• P0232 Fuel Pump Secondary Circuit High: High voltage in the fuel pump secondary circuit.
• P0233 Fuel Pump Secondary Circuit Intermittent: Intermittent issue in the fuel pump secondary circuit.
• P0234 Turbo/Super Charger Overboost Condition: Turbo or supercharger is producing excessive boost pressure. (Less relevant for a stock 2001 Impala)
• (P0235 – P0242): These codes relate to Turbo/Super Charger Boost Sensor A & B Circuits, indicating circuit malfunctions, range/performance issues, and signal problems with the boost pressure sensors. (Less relevant for a stock 2001 Impala)
• (P0243 – P0250): These codes are for Turbo/Super Charger Wastegate Solenoid A & B, covering circuit malfunctions, range/performance, and low/high voltage issues with the wastegate solenoids which control boost pressure. (Less relevant for a stock 2001 Impala)

P0251 – P0299: Injection Pump Fuel Metering Control & Cylinder Injector Circuit Low/High Issues

The final part of the P0200 series (P0251 to P0299) addresses Injection Pump Fuel Metering Control (more relevant for diesel engines, less so for a gasoline 2001 Impala) and Cylinder Injector Circuit Low/High issues, as well as misfire and overspeed conditions.

• (P0251 – P0260): These codes are related to Injection Pump Fuel Metering Control A & B, covering range/performance, low/high voltage, and intermittent issues. Less relevant for a standard gasoline 2001 Impala.
• P0261 Cylinder 1 Injector Circuit Low: Low voltage in the injector circuit for cylinder 1.
• P0262 Cylinder 1 Injector Circuit High: High voltage in the injector circuit for cylinder 1.
• P0263 Cylinder 1 Contribution/Balance: Cylinder 1 is not contributing equally to engine power compared to other cylinders. This can be due to injector problems, compression issues, or other cylinder-specific problems.
• (P0264 – P0296): These codes continue the pattern from P0261-P0263, covering Injector Circuit Low/High and Contribution/Balance issues for cylinders 2 through 12. Again, codes beyond P0206 or P0208 are less relevant for a standard 2001 Impala engine.
• P0297 Vehicle Overspeed Condition: Vehicle speed is too high, possibly exceeding a set limit.
• P0298 Engine Oil Overtemperature Condition: Engine oil temperature is excessively high.
• P0299 Turbo / Super Charger Underboost: Turbocharger or supercharger is not producing enough boost pressure. (Less relevant for a stock 2001 Impala)

Decoding 2001 Chevy Impala OBD2 Codes: The P0300 Series

The P0300 series OBD2 codes are primarily focused on misfires in your 2001 Chevy Impala engine. Misfires occur when one or more cylinders fail to ignite the air-fuel mixture properly. This can result in rough idling, reduced power, poor fuel economy, and potential damage to the catalytic converter.

P0300 – P0312: Random and Cylinder-Specific Misfire Detected

This range (P0300 to P0312) covers both random misfires and misfires specific to individual cylinders.

• P0300 Random Misfire Detected: Indicates that misfires are occurring in multiple cylinders or the system cannot pinpoint a specific cylinder. This is often the first misfire code you might see.
• P0301 Cylinder 1 Misfire Detected: Misfire is specifically detected in cylinder 1.
• P0302 Cylinder 2 Misfire Detected: Misfire in cylinder 2.
• P0303 Cylinder 3 Misfire Detected: Misfire in cylinder 3.
• P0304 Cylinder 4 Misfire Detected: Misfire in cylinder 4.
• P0305 Cylinder 5 Misfire Detected: Misfire in cylinder 5.
• P0306 Cylinder 6 Misfire Detected: Misfire in cylinder 6.
• (P0307 – P0312): These codes continue the pattern for misfires detected in cylinders 7 through 12. Less relevant for a standard 2001 Impala engine.

P0313 – P0316: Misfire Conditions Related to Fuel, Cylinder, and Startup

Codes P0313 through P0316 address specific misfire scenarios, such as misfires under low fuel conditions, in unspecified cylinders, or during startup.

• P0313 Misfire Detected with Low Fuel: Misfires are occurring when the fuel level is low, suggesting a potential fuel delivery issue related to low fuel quantity.
• P0314 Single Cylinder Misfire (Cylinder not Specified): A misfire is detected, but the system cannot identify which cylinder is misfiring.
• P0315 Crankshaft Position System Variation Not Learned: The PCM has not learned the crankshaft position system variations, which is needed for accurate misfire detection. This might require a relearn procedure.
• P0316 Misfire Detected On Startup (First 1000 Revolutions): Misfires are occurring specifically during engine startup within the first 1000 engine revolutions.

P0317 – P0399: Rough Road Hardware, Ignition/Distributor, Knock Sensor, and Crank/Camshaft Position Sensor Issues

The remaining codes in the P0300 series (P0317 to P0399) cover a diverse range of systems, including rough road sensors (less common), ignition/distributor circuits, knock sensors, and crankshaft/camshaft position sensors. These systems are all crucial for engine management, performance, and safety.

• P0317 Rough Road Hardware Not Present: Indicates that the rough road sensor hardware, if equipped, is not present when expected. (Less common feature).
• P0318 Rough Road Sensor A Signal Circuit: Circuit issue with Rough Road Sensor A.
• P0319 Rough Road Sensor B Signal Circuit: Circuit issue with Rough Road Sensor B.
• P0320 Ignition/Distributor Engine Speed Input Circuit: Circuit malfunction in the ignition or distributor engine speed input circuit.
• P0321 Ignition/Distributor Engine Speed Input Circuit Range/Performance: Performance issue with the ignition/distributor engine speed input circuit.
• P0322 Ignition/Distributor Engine Speed Input Circuit No Signal: No signal from the ignition/distributor engine speed input circuit.
• P0323 Ignition/Distributor Engine Speed Input Circuit Intermittent: Intermittent signal from the ignition/distributor engine speed input circuit.
• P0324 Knock Control System Error: General error in the knock control system. Knock control protects the engine from damaging detonation.
• P0325 Knock Sensor 1 Circuit (Bank 1): Circuit issue with Knock Sensor 1 on Bank 1.
• P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1): Performance issue with Knock Sensor 1 on Bank 1.
• P0327 Knock Sensor 1 Circuit Low Input (Bank 1): Low input signal from Knock Sensor 1 on Bank 1.
• P0328 Knock Sensor 1 Circuit High Input (Bank 1): High input signal from Knock Sensor 1 on Bank 1.
• P0329 Knock Sensor 1 Circuit Intermittent (Bank 1): Intermittent signal from Knock Sensor 1 on Bank 1.
• (P0330 – P0334): These codes mirror P0325-P0329 but are for Knock Sensor 2 (Bank 2), indicating similar circuit malfunctions, range/performance issues, and signal problems but for Knock Sensor 2.
• P0335 Crankshaft Position Sensor A Circuit: Circuit issue with Crankshaft Position Sensor A.
• P0336 Crankshaft Position Sensor A Circuit Range/Performance: Performance issue with Crankshaft Position Sensor A.
• P0337 Crankshaft Position Sensor A Circuit Low Input: Low input signal from Crankshaft Position Sensor A.
• P0338 Crankshaft Position Sensor A Circuit High Input: High input signal from Crankshaft Position Sensor A.
• P0339 Crankshaft Position Sensor A Circuit Intermittent: Intermittent signal from Crankshaft Position Sensor A.
• P0340 Camshaft Position Sensor A Circuit (Bank 1 or single sensor): Circuit issue with Camshaft Position Sensor A (Bank 1 or single sensor if only one camshaft sensor).
• P0341 Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or single sensor): Performance issue with Camshaft Position Sensor A.
• P0342 Camshaft Position Sensor A Circuit Low Input (Bank 1 or single sensor): Low input signal from Camshaft Position Sensor A.
• P0343 Camshaft Position Sensor A Circuit High Input (Bank 1 or single sensor): High input signal from Camshaft Position Sensor A.
• P0344 Camshaft Position Sensor A Circuit Intermittent (Bank 1 or single sensor): Intermittent signal from Camshaft Position Sensor A.
• (P0345 – P0349): These codes mirror P0340-P0344 but are for Camshaft Position Sensor A (Bank 2), indicating similar circuit malfunctions, range/performance issues, and signal problems but for Camshaft Position Sensor A on Bank 2.
• P0350 Ignition Coil Primary/Secondary Circuit: General circuit malfunction in the ignition coil primary or secondary circuit. This is a broad code.
• (P0351 – P0362): These codes continue the pattern from P0350, but are specific to individual Ignition Coils A through L. For a 2001 Impala, codes up to P0356 (for V6) or P0358 (for common V8s) are most relevant. They indicate primary/secondary circuit malfunctions for specific ignition coils.
• P0363 Misfire Detected – Fueling Disabled: Misfire detected, and the PCM has disabled fueling to the affected cylinder(s) to protect the catalytic converter.
• P0365 Camshaft Position Sensor B Circuit (Bank 1): Circuit issue with Camshaft Position Sensor B on Bank 1.
• P0366 Camshaft Position Sensor B Circuit Range/Performance (Bank 1): Performance issue with Camshaft Position Sensor B on Bank 1.
• P0367 Camshaft Position Sensor B Circuit Low Input (Bank 1): Low input signal from Camshaft Position Sensor B on Bank 1.
• P0368 Camshaft Position Sensor B Circuit High Input (Bank 1): High input signal from Camshaft Position Sensor B on Bank 1.
• P0369 Camshaft Position Sensor B Circuit Intermittent (Bank 1): Intermittent signal from Camshaft Position Sensor B on Bank 1.
• (P0370 – P0379): These codes are related to Timing Reference High Resolution Signal A & B, indicating issues with the timing reference signals used for precise engine control.
• P0380 Glow Plug/Heater Circuit A: Circuit issue with Glow Plug/Heater Circuit A (diesel engines, less relevant for gasoline 2001 Impala).
• P0381 Glow Plug/Heater Indicator Circuit: Indicator circuit issue for glow plugs (diesel engines, less relevant for gasoline 2001 Impala).
• P0382 Glow Plug/Heater Circuit B: Circuit issue with Glow Plug/Heater Circuit B (diesel engines, less relevant for gasoline 2001 Impala).
• (P0385 – P0389): These codes mirror P0335-P0339 but are for Crankshaft Position Sensor B Circuit, indicating similar circuit malfunctions, range/performance issues, and signal problems but for Crankshaft Position Sensor B.
• (P0390 – P0394): These codes mirror P0345-P0349 but are for Camshaft Position Sensor B (Bank 2), indicating similar circuit malfunctions, range/performance issues, and signal problems for Camshaft Position Sensor B on Bank 2.

Decoding 2001 Chevy Impala OBD2 Codes: The P0400 Series

The P0400 series OBD2 codes for the 2001 Chevy Impala largely address issues within the emissions control systems, particularly the Exhaust Gas Recirculation (EGR) system, Secondary Air Injection (SAI) system, Evaporative Emission (EVAP) system, and Catalyst system. These systems are crucial for reducing harmful pollutants released into the atmosphere.

P0400 – P0409: Exhaust Gas Recirculation (EGR) System Issues

This range (P0400 to P0409) focuses on the EGR system. The EGR system recirculates a portion of the exhaust gas back into the intake manifold to lower combustion temperatures and reduce NOx emissions.

• P0400 Exhaust Gas Recirculation Flow: General issue with EGR flow. This code can indicate insufficient or excessive EGR flow.
• P0401 Exhaust Gas Recirculation Flow Insufficient Detected: Insufficient EGR flow is detected. This can be due to a clogged EGR valve, vacuum leaks, or other EGR system problems.
• P0402 Exhaust Gas Recirculation Flow Excessive Detected: Excessive EGR flow is detected. This is less common but can be caused by a stuck-open EGR valve or related issues.
• P0403 Exhaust Gas Recirculation Control Circuit: Malfunction in the EGR control circuit.
• P0404 Exhaust Gas Recirculation Control Circuit Range/Performance: Performance issue with the EGR control circuit.
• P0405 Exhaust Gas Recirculation Sensor A Circuit Low: Low voltage signal from EGR Sensor A circuit.
• P0406 Exhaust Gas Recirculation Sensor A Circuit High: High voltage signal from EGR Sensor A circuit.
• P0407 Exhaust Gas Recirculation Sensor B Circuit Low: Low voltage signal from EGR Sensor B circuit.
• P0408 Exhaust Gas Recirculation Sensor B Circuit High: High voltage signal from EGR Sensor B circuit.
• P0409 Exhaust Gas Recirculation Sensor A Circuit: Circuit issue with EGR Sensor A.

P0410 – P0419: Secondary Air Injection (SAI) System Issues

Codes P0410 through P0419 relate to the Secondary Air Injection (SAI) system. The SAI system pumps fresh air into the exhaust system during cold starts to help the catalytic converter reach operating temperature quickly and reduce emissions.

• P0410 Secondary Air Injection System: General malfunction in the SAI system.
• P0411 Secondary Air Injection Incorrect Upstream Flow Detected: Incorrect upstream flow detected in the SAI system, suggesting a blockage or malfunction.
• P0412 Secondary Air Injection Switching Valve A Circuit: Malfunction in Switching Valve A circuit.
• P0413 Secondary Air Injection Switching Valve A Circuit Open: Open circuit in Switching Valve A.
• P0414 Secondary Air Injection Switching Valve A Circuit Shorted: Short circuit in Switching Valve A.
• P0415 Secondary Air Injection Switching Valve B Circuit: Malfunction in Switching Valve B circuit (if equipped with a second valve).
• P0416 Secondary Air Injection Switching Valve B Circuit Open: Open circuit in Switching Valve B.
• P0417 Secondary Air Injection Switching Valve B Circuit Shorted: Short circuit in Switching Valve B.
• P0418 Secondary Air Injection System Control A Circuit: Malfunction in SAI Control Circuit A (pump relay or driver circuit).
• P0419 Secondary Air Injection System Control B Circuit: Malfunction in SAI Control Circuit B (if applicable).

P0420 – P0439: Catalyst System Efficiency Issues

This section (P0420 to P0439) addresses Catalyst System Efficiency Below Threshold codes, specifically for Bank 1 and Bank 2. The catalytic converter is a crucial emissions component that reduces harmful gases in the exhaust.

• P0420 Catalyst System Efficiency Below Threshold (Bank 1): The catalytic converter on Bank 1 is not performing at its expected efficiency level. This is a common code often indicating a failing or inefficient catalytic converter.
• P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1): The warm-up catalyst (if equipped) on Bank 1 is not performing efficiently.
• P0422 Main Catalyst Efficiency Below Threshold (Bank 1): The main catalytic converter on Bank 1 is inefficient.
• P0423 Heated Catalyst Efficiency Below Threshold (Bank 1): The heated catalyst (if equipped) on Bank 1 is inefficient.
• P0424 Heated Catalyst Temperature Below Threshold (Bank 1): The heated catalyst on Bank 1 is not reaching its required temperature.
• P0425 Catalyst Temperature Sensor (Bank 1): Circuit issue with the catalyst temperature sensor on Bank 1 (if equipped).
• P0426 Catalyst Temperature Sensor Range/Performance (Bank1): Performance issue with Bank 1 catalyst temperature sensor.
• P0427 Catalyst Temperature Sensor Low Input (Bank 1): Low input signal from Bank 1 catalyst temperature sensor.
• P0428 Catalyst Temperature Sensor High Input (Bank 1): High input signal from Bank 1 catalyst temperature sensor.
• P0429 Catalyst Heater Control Circuit (Bank 1): Circuit issue with the catalyst heater control circuit on Bank 1 (if equipped with a heated catalyst).
• (P0430 – P0439): These codes mirror P0420-P0429 but are for Bank 2, indicating the same types of catalyst efficiency and temperature sensor issues but for the catalytic converter on Bank 2.

P0440 – P0479: Evaporative Emission (EVAP) System & Exhaust Pressure Issues

Codes P0440 through P0479 cover a wide range of issues, primarily related to the Evaporative Emission (EVAP) system and Exhaust Pressure sensors/valves. The EVAP system prevents fuel vapors from escaping into the atmosphere.

• P0440 Evaporative Emission System: General malfunction in the EVAP system. This is a common code often indicating a leak in the system.
• P0441 Evaporative Emission System Incorrect Purge Flow: Incorrect purge flow in the EVAP system, often due to a problem with the purge valve or related components.
• P0442 Evaporative Emission System Leak Detected (small leak): A small leak is detected in the EVAP system.
• P0443 Evaporative Emission System Purge Control Valve Circuit: Circuit issue with the EVAP purge control valve.
• P0444 Evaporative Emission System Purge Control Valve Circuit Open: Open circuit in the purge control valve.
• P0445 Evaporative Emission System Purge Control Valve Circuit Shorted: Short circuit in the purge control valve.
• P0446 Evaporative Emission System Vent Control Circuit: Circuit issue with the EVAP vent control circuit.
• P0447 Evaporative Emission System Vent Control Circuit Open: Open circuit in the vent control valve.
• P0448 Evaporative Emission System Vent Control Circuit Shorted: Short circuit in the vent control valve.
• P0449 Evaporative Emission System Vent Control Circuit Intermittent: Intermittent issue in the vent control circuit.
• P0450 Evaporative Emission System Pressure Sensor/Switch: Circuit issue with the EVAP pressure sensor or switch.
• P0451 Evaporative Emission System Pressure Sensor/Switch Range/Performance: Performance issue with the EVAP pressure sensor/switch.
• P0452 Evaporative Emission System Pressure Sensor/Switch Low Input: Low input signal from the EVAP pressure sensor/switch.
• P0453 Evaporative Emission System Pressure Sensor/Switch High Input: High input signal from the EVAP pressure sensor/switch.
• P0454 Evaporative Emission System Pressure Sensor/Switch Intermittent: Intermittent signal from the EVAP pressure sensor/switch.
• P0455 Evaporative Emission System Leak Detected (gross leak/no flow): A large leak is detected in the EVAP system.
• P0456 Evaporative Emission System Leak Detected (very small leak): A very small leak is detected in the EVAP system.
• P0457 Evaporative Emission System Leak Detected (fuel cap loose/off): EVAP leak detected, specifically indicating a loose or missing fuel cap.
• P0458 Evaporative Emission System Purge Control Valve Circuit Low: Low voltage in the purge control valve circuit.
• P0459 Evaporative Emission System Purge Control Valve Circuit High: High voltage in the purge control valve circuit.
• P0460 Fuel Level Sensor A Circuit: Circuit issue with Fuel Level Sensor A.
• P0461 Fuel Level Sensor A Circuit Range/Performance: Performance issue with Fuel Level Sensor A.
• P0462 Fuel Level Sensor A Circuit Low Input: Low input signal from Fuel Level Sensor A, often causing inaccurate fuel gauge readings.
• P0463 Fuel Level Sensor A Circuit High Input: High input signal from Fuel Level Sensor A.
• P0464 Fuel Level Sensor A Circuit Intermittent: Intermittent signal from Fuel Level Sensor A.
• P0465 Evaporative Emission System Purge Flow Sensor Circuit: Circuit issue with the EVAP purge flow sensor (if equipped).
• P0466 Evaporative Emission System Purge Flow Sensor Circuit Range/Performance: Performance issue with EVAP purge flow sensor.
• P0467 Evaporative Emission System Purge Flow Sensor Circuit Low Input: Low input signal from EVAP purge flow sensor.
• P0468 Evaporative Emission System Purge Flow Sensor Circuit High Input: High input signal from EVAP purge flow sensor.
• P0469 Evaporative Emission System Purge Flow Sensor Circuit Intermittent: Intermittent signal from EVAP purge flow sensor.
• P0470 Exhaust Pressure Sensor: Circuit issue with the exhaust pressure sensor (diesel engines, less relevant for gasoline 2001 Impala unless modified).
• P0471 Exhaust Pressure Sensor Range/Performance: Performance issue with exhaust pressure sensor.
• P0472 Exhaust Pressure Sensor Low Input: Low input from exhaust pressure sensor.
• P0473 Exhaust Pressure Sensor High Input: High input from exhaust pressure sensor.
• P0474 Exhaust Pressure Sensor Intermittent: Intermittent signal from exhaust pressure sensor.
• P0475 Exhaust Pressure Control Valve: Circuit issue with the exhaust pressure control valve (diesel engines, less relevant for gasoline 2001 Impala unless modified).
• P0476 Exhaust Pressure Control Valve Range/Performance: Performance issue with exhaust pressure control valve.
• P0477 Exhaust Pressure Control Valve Low Input: Low input to exhaust pressure control valve circuit.
• P0478 Exhaust Pressure Control Valve High Input: High input to exhaust pressure control valve circuit.
• P0479 Exhaust Pressure Control Valve Intermittent: Intermittent issue with exhaust pressure control valve.

P0480 – P0499: Fan Control, EGR Throttle, and SAI Insufficient Flow Issues

The final section of the P0400 series (P0480 to P0499) covers cooling fan control circuits, EGR throttle position control, and Secondary Air Injection insufficient flow issues.

• P0480 Fan 1 Control Circuit: Circuit issue with Fan 1 control circuit (cooling fan).
• P0481 Fan 2 Control Circuit: Circuit issue with Fan 2 control circuit (if equipped with dual fans).
• P0482 Fan 3 Control Circuit: Circuit issue with Fan 3 control circuit (less common).
• P0483 Fan Performance: Cooling fan performance issue.
• P0484 Fan Current: Cooling fan current issue (overcurrent or undercurrent).
• P0485 Fan Power/Ground Circuit: Cooling fan power or ground circuit issue.
• P0486 Exhaust Gas Recirculation Sensor B Circuit: Circuit issue with EGR Sensor B.
• P0487 EGR Throttle Position Control Circuit: Circuit issue with EGR throttle position control.
• P0488 EGR Throttle Position Control Range/Performance: Performance issue with EGR throttle position control.
• P0489 Exhaust Gas Recirculation Control Circuit Low: Low voltage in EGR control circuit.
• P0490 Exhaust Gas Recirculation Control Circuit High: High voltage in EGR control circuit.
• P0491 Secondary Air Injection System Insufficient Flow (Bank 1): Insufficient SAI flow detected on Bank 1.
• P0492 Secondary Air Injection System Insufficient Flow (Bank 2): Insufficient SAI flow on Bank 2 (if applicable).
• P0493 Fan Overspeed (clutch locked): Cooling fan overspeed condition, possibly due to a locked fan clutch (if equipped).
• P0494 Fan Speed Low: Cooling fan speed is lower than expected.
• P0495 Fan Speed High: Cooling fan speed is higher than expected.
• P0496 Evaporative Emission System High Purge Flow: High purge flow detected in the EVAP system.
• P0497 Evaporative Emission System Low Purge Flow: Low purge flow detected in the EVAP system.
• P0498 Evaporative Emission System Vent Control Circuit Low: Low voltage in EVAP vent control circuit.
• P0499 Evaporative Emission System Vent Control Circuit High: High voltage in EVAP vent control circuit.

Decoding 2001 Chevy Impala OBD2 Codes: The P0500 Series

The P0500 series OBD2 codes for your 2001 Chevy Impala primarily address vehicle speed sensor (VSS) issues, idle air control (IAC) system problems, cruise control malfunctions, and various sensor circuit faults. These systems are critical for vehicle operation, performance, and driver assistance features.

P0500 – P0503: Vehicle Speed Sensor (VSS) Issues

This range (P0500 to P0503) focuses on the Vehicle Speed Sensor (VSS). The VSS measures the speed of the vehicle and provides this information to the PCM, ABS module, and other systems.

• P0500 Vehicle Speed Sensor A: General malfunction in Vehicle Speed Sensor A circuit.
• P0500 Vehicle Speed Signal Not Detected: No vehicle speed signal is being detected.
• P0501 Vehicle Speed Sensor A Range/Performance: Vehicle Speed Sensor A reading is out of the expected range or performance.
• P0502 Vehicle Speed Sensor A Circuit Low Input: Low voltage signal from Vehicle Speed Sensor A, indicating a low or no speed reading.
• P0503 Vehicle Speed Sensor A Intermittent/Erratic/High: Intermittent, erratic, or high voltage signal from Vehicle Speed Sensor A.

P0504 – P0509: Brake Switch Correlation and Idle Air Control (IAC) System Issues

Codes P0504 through P0509 cover Brake Switch A/B Correlation problems and Idle Air Control (IAC) system malfunctions.

• P0504 Brake Switch A / B Correlation: Mismatch in signals between Brake Switch A and Brake Switch B. This can affect cruise control, torque converter lockup, and other systems that rely on brake switch input.
• P0505 Idle Air Control System: General malfunction in the Idle Air Control (IAC) system. The IAC valve controls the amount of air bypassing the throttle plate at idle to maintain a stable idle speed.
• P0506 Idle Air Control System RPM Lower Than Expected: Idle RPM is lower than the desired or expected RPM, possibly due to a stuck or malfunctioning IAC valve, vacuum leaks, or other issues.
• P0507 Idle Air Control System RPM Higher Than Expected: Idle RPM is higher than expected, potentially caused by a stuck-open IAC valve, vacuum leaks, or throttle body issues.
• P0508 Idle Air Control System Circuit Low: Low voltage in the IAC system circuit.
• P0509 Idle Air Control System Circuit High: High voltage in the IAC system circuit.

P0510 – P0513: Closed Throttle Position Switch, IAC Circuit, Starter Request, and Immobilizer Key Issues

This section (P0510 to P0513) addresses Closed Throttle Position Switch problems, general IAC circuit issues, Starter Request circuit malfunctions, and Incorrect Immobilizer Key detection.

• P0510 Closed Throttle Position Switch: Malfunction in the Closed Throttle Position Switch circuit. This switch confirms when the throttle is fully closed.
• P0511 Idle Air Control Circuit: General circuit issue with the Idle Air Control circuit. This is similar to P0505 but more focused on circuit problems.
• P0512 Starter Request Circuit: Malfunction in the Starter Request circuit. This circuit signals the PCM to initiate the engine starting process.
• P0513 Incorrect Immobilizer Key: The immobilizer system has detected an incorrect or unprogrammed key being used to start the vehicle. This is a security feature to prevent theft.

P0514 – P0529: Battery Temperature, Idle Air Control Performance, and Fan Speed Sensor Issues

Codes P0514 through P0529 cover Battery Temperature Sensor circuit problems, Idle Air Control System Performance issues, Engine Oil Pressure sensor/switch faults, Cruise Control Servo Control circuit malfunctions, and Fan Speed Sensor circuit problems.

• P0514 Battery Temperature Sensor Circuit Range/Performance: Battery Temperature Sensor reading is out of range or performance is abnormal.
• P0515 Battery Temperature Sensor Circuit: Circuit issue with the Battery Temperature Sensor.
• P0516 Battery Temperature Sensor Circuit Low: Low voltage in the Battery Temperature Sensor circuit.
• P0517 Battery Temperature Sensor Circuit High: High voltage in the Battery Temperature Sensor circuit.
• P0518 Idle Air Control Circuit Intermittent: Intermittent issue in the Idle Air Control circuit.
• P0519 Idle Air Control Circuit System Performance: Overall performance issue with the Idle Air Control system.
• P0520 Engine Oil Pressure Sensor/Switch Circuit: Circuit issue with the Engine Oil Pressure Sensor or Switch.
• P0521 Engine Oil Pressure Sensor/Switch Circuit Range/Performance: Performance issue with the Engine Oil Pressure Sensor/Switch.
• P0522 Engine Oil Pressure Sensor/Switch Circuit Low Input: Low input signal from the Engine Oil Pressure Sensor/Switch, indicating low oil pressure (or sensor fault).
• P0523 Engine Oil Pressure Sensor/Switch Circuit High Input: High input signal, suggesting high oil pressure (or sensor fault).
• P0524 Engine Oil Pressure Too Low: Engine oil pressure is critically low. This is a serious condition that can cause engine damage.
• P0525 Cruise Control Servo Control Circuit Range/Performance: Performance issue with the Cruise Control Servo Control circuit.
• P0526 Fan Speed Sensor Circuit: Circuit issue with the Fan Speed Sensor circuit.
• P0527 Fan Speed Sensor Circuit Range/Performance: Performance issue with the Fan Speed Sensor circuit.
• P0528 Fan Speed Sensor Circuit No Signal: No signal from the Fan Speed Sensor circuit.
• P0529 Fan Speed Sensor Circuit Intermittent: Intermittent signal from the Fan Speed Sensor circuit.

P0530 – P0559: A/C Refrigerant Pressure, Evaporator Temperature, Intake Air Heater, Exhaust Gas Temperature, and Power Steering Pressure Sensor Issues

Codes P0530 through P0559 cover a diverse set of sensor and circuit issues, including A/C Refrigerant Pressure Sensor problems, A/C Evaporator Temperature Sensor faults, Intake Air Heater circuits (diesel, less relevant for gasoline 2001 Impala), Exhaust Gas Temperature sensors (diesel, less relevant for gasoline 2001 Impala), and Power Steering Pressure Sensor malfunctions.

• P0530 A/C Refrigerant Pressure Sensor A Circuit: Circuit issue with A/C Refrigerant Pressure Sensor A.
• P0531 A/C Refrigerant Pressure Sensor A Circuit Range/Performance: Performance issue with A/C Refrigerant Pressure Sensor A.
• P0532 A/C Refrigerant Pressure Sensor A Circuit Low Input: Low input signal from A/C Refrigerant Pressure Sensor A, indicating low refrigerant pressure.
• P0533 A/C Refrigerant Pressure Sensor A Circuit High Input: High input signal, suggesting high refrigerant pressure.
• P0534 A/C Refrigerant Charge Loss: Indicates a loss of A/C refrigerant charge (leak in the A/C system).
• P0535 A/C Evaporator Temperature Sensor Circuit: Circuit issue with A/C Evaporator Temperature Sensor.
• P0536 A/C Evaporator Temperature Sensor Circuit Range/Performance: Performance issue with A/C Evaporator Temperature Sensor.
• P0537 A/C Evaporator Temperature Sensor Circuit Low: Low voltage from A/C Evaporator Temperature Sensor, suggesting a low evaporator temperature.
• P0538 A/C Evaporator Temperature Sensor Circuit High: High voltage, indicating a high evaporator temperature.
• P0539 A/C Evaporator Temperature Sensor Circuit Intermittent: Intermittent signal from A/C Evaporator Temperature Sensor.
• P0540 Intake Air Heater A Circuit: Circuit issue with Intake Air Heater A (diesel engines, less relevant for gasoline 2001 Impala).
• P0541 Intake Air Heater A Circuit Low: Low voltage in Intake Air Heater A circuit.
• P0542 Intake Air Heater A Circuit High: High voltage in Intake Air Heater A circuit.
• P0543 Intake Air Heater A Circuit Open: Open circuit in Intake Air Heater A circuit.
• P0544 Exhaust Gas Temperature Sensor Circuit – Bank 1 Sensor 1: Circuit issue with Exhaust Gas Temperature Sensor – Bank 1 Sensor 1 (diesel engines, less relevant for gasoline 2001 Impala unless modified).
• P0545 Exhaust Gas Temperature Sensor Circuit Low – Bank 1 Sensor 1: Low voltage from Exhaust Gas Temperature Sensor – Bank 1 Sensor 1.
• P0546 Exhaust Gas Temperature Sensor Circuit High – Bank 1 Sensor 1: High voltage from Exhaust Gas Temperature Sensor – Bank 1 Sensor 1.
• (P0547 – P0549): These codes mirror P0544-P0546 but are for Exhaust Gas Temperature Sensor – Bank 2 Sensor 1, if equipped.
• P0550 Power Steering Pressure Sensor/Switch Circuit: Circuit issue with Power Steering Pressure Sensor or Switch.
• P0551 Power Steering Pressure Sensor/Switch Circuit Range/Performance: Performance issue with Power Steering Pressure Sensor/Switch.
• P0552 Power Steering Pressure Sensor/Switch Circuit Low Input: Low input signal from Power Steering Pressure Sensor/Switch, indicating low power steering pressure (or sensor fault).
• P0553 Power Steering Pressure Sensor/Switch Circuit High Input: High input signal, suggesting high power steering pressure.
• P0554 Power Steering Pressure Sensor/Switch Circuit Intermittent: Intermittent signal from Power Steering Pressure Sensor/Switch.
• P0555 Brake Booster Pressure Sensor Circuit: Circuit issue with Brake Booster Pressure Sensor.
• P0556 Brake Booster Pressure Sensor Circuit Range/Performance: Performance issue with Brake Booster Pressure Sensor.
• P0557 Brake Booster Pressure Sensor Circuit Low Input: Low input signal from Brake Booster Pressure Sensor, indicating low brake booster pressure (or sensor fault).
• P0558 Brake Booster Pressure Sensor Circuit High Input: High input signal, suggesting high brake booster pressure.
• P0559 Brake Booster Pressure Sensor Circuit Intermittent: Intermittent signal from Brake Booster Pressure Sensor.

Decoding 2001 Chevy Impala OBD2 Codes: The P0600 Series

The P0600 series OBD2 codes for your 2001 Chevy Impala are largely focused on internal control module (PCM/ECM/TCM) malfunctions, circuit issues related to power relays, generators, fuel pumps, throttle actuators, sensors, and various output circuits. These codes often indicate more complex electronic problems within the vehicle’s computer systems.

P0600 – P0609: Serial Communication Link & PCM/ECM/TCM Internal Faults

This range (P0600 to P0609) addresses Serial Communication Link issues and internal faults within the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM).

• P0600 Serial Communication Link: General malfunction in the serial communication link. This indicates a problem with data communication between different modules in the vehicle’s network.
• P0601 Internal Control Module Memory Check Sum Error: Internal PCM/ECM/TCM memory checksum error. This indicates a problem with the integrity of the control module’s memory, possibly requiring module replacement or reprogramming.
• P0602 Powertrain Control Module Programming Error: PCM programming error. The PCM may not be programmed correctly or the programming may be corrupted.
• P0603 Powertrain Control Module Keep Alive Memory (KAM) Error: PCM Keep Alive Memory (KAM) error. KAM stores learned information and settings, and an error here can cause various driveability issues.
• P0604 Powertrain Control Module Random Access Memory (RAM) Error: PCM Random Access Memory (RAM) error. RAM is used for temporary data storage during operation, and an error here indicates a module malfunction.
• P0605 Powertrain Control Module Read Only Memory (ROM) Error: PCM Read Only Memory (ROM) error. ROM stores the permanent operating instructions for the PCM, and an error here is serious.
• P0606 ECM / PCM Processor: ECM or PCM processor fault. Indicates a hardware failure within the control module’s processor.
• P0607 Control Module Performance: General performance issue with the control module (PCM/ECM/TCM).
• P0608 Powertrain Control Module Vehicle Speed Output A: PCM Vehicle Speed Output A circuit issue.
• P0609 Powertrain Control Module Vehicle Speed Output B: PCM Vehicle Speed Output B circuit issue.

P0610 – P0629: Control Module Vehicle Options, Fuel Injector Control, TCM Processor, Starter Relay, and Generator Control Issues

Codes P0610 through P0629 cover Control Module Vehicle Options errors, Fuel Injector Control Module problems, TCM Processor faults, Starter Relay circuit issues, and Generator (alternator) Control circuit malfunctions.

• P0610 Control Module Vehicle Options Error: Vehicle options programming error in the control module. The PCM may be configured incorrectly for the vehicle’s options.
• P0611 Fuel Injector Control Module Performance: Performance issue with the Fuel Injector Control Module (FICM), if equipped (some diesel engines). Less likely on a standard 2001 Impala.
• P0612 Fuel Injector Control Module Relay Control Circuit: FICM relay control circuit issue.
• P0613 TCM Processor: Transmission Control Module (TCM) processor fault. Indicates a hardware failure within the TCM processor.
• P0614 ECM / TCM Incompatible: ECM and TCM are incompatible or not communicating correctly.
• P0615 Starter Relay Circuit: Malfunction in the Starter Relay circuit.
• P0616 Starter Relay Circuit Low: Low voltage in the Starter Relay circuit.
• P0617 Starter Relay Circuit High: High voltage in the Starter Relay circuit.
• P0618 Alternative Fuel Control Module KAM Error: KAM error in the Alternative Fuel Control Module (if equipped for flex-fuel or other alternative fuels).
• P0619 Alternative Fuel Control Module RAM/ROM Error: RAM or ROM error in the Alternative Fuel Control Module.
• P0620 Generator Control Circuit: Malfunction in the Generator (alternator) Control circuit.
• P0621 Generator Lamp Terminal Circuit: Circuit issue with the generator lamp terminal circuit (charging system warning light).
• P0622 Generator Field Terminal Circuit: Circuit issue with the generator field terminal circuit (alternator field control).
• P0623 Generator Lamp Control Circuit: Control circuit issue for the generator warning lamp.
• P0624 Fuel Cap Lamp Control Circuit: Control circuit issue for the fuel cap warning lamp (EVAP system related).
• P0625 Generator Field Terminal Circuit Low: Low voltage in the generator field terminal circuit.
• P0626 Generator Field Terminal Circuit High: High voltage in the generator field terminal circuit.
• P0627 Fuel Pump A Control Circuit / Open: Open circuit in Fuel Pump A control circuit.
• P0628 Fuel Pump A Control Circuit Low: Low voltage in Fuel Pump A control circuit.
• P0629 Fuel Pump A Control Circuit High: High voltage in Fuel Pump A control circuit.

P0630 – P0649: VIN Incompatibility, Odometer/Immobilizer Programming, PCM/ECM/TCM Temperature, Power Steering Control, Throttle Actuator Control, and Intake Air Heater Control Issues

Codes P0630 through P0649 cover VIN Incompatibility errors, Odometer/Immobilizer programming problems, PCM/ECM/TCM Internal Temperature issues, Power Steering Control Circuit malfunctions, Throttle Actuator Control problems, Intake Air Heater Control circuits, and Sensor Reference Voltage Circuit faults.

• P0630 VIN Not Programmed or Incompatible – ECM/PCM: Vehicle Identification Number (VIN) is not programmed in the ECM/PCM or is incompatible. This often occurs after ECM/PCM replacement.
• P0631 VIN Not Programmed or Incompatible – TCM: VIN is not programmed or incompatible in the TCM.
• P0632 Odometer Not Programmed – ECM/PCM: Odometer information is not programmed in the ECM/PCM.
• P0633 Immobilizer Key Not Programmed – ECM/PCM: Immobilizer key information is not programmed in the ECM/PCM.
• P0634 PCM / ECM / TCM Internal Temperature Too High: Internal temperature of the PCM, ECM, or TCM is excessively high, potentially due to overheating or module failure.
• P0635 Power Steering Control Circuit: Malfunction in the Power Steering Control circuit.
• P0636 Power Steering Control Circuit Low: Low voltage in the Power Steering Control circuit.
• P0637 Power Steering Control Circuit High: High voltage in the Power Steering Control circuit.
• P0638 Throttle Actuator Control Range/Performance – Bank 1: Performance issue with the Throttle Actuator Control system on Bank 1 (if applicable, some vehicles have dual throttle bodies).
• P0639 Throttle Actuator Control Range/Performance – Bank 2: Performance issue on Bank 2.
• P0640 Intake Air Heater Control Circuit: Malfunction in the Intake Air Heater Control circuit (diesel engines, less relevant for gasoline 2001 Impala).
• P0641 Sensor Reference Voltage A Circuit/Open: Open circuit or malfunction in Sensor Reference Voltage A circuit. This circuit provides a stable voltage supply to multiple sensors, and a problem here can cause multiple sensor codes.
• P0642 Sensor Reference Voltage A Circuit Low: Low voltage in Sensor Reference Voltage A circuit.
• P0643 Sensor Reference Voltage A Circuit High: High voltage in Sensor Reference Voltage A circuit.
• P0644 Driver Display Serial Communication Circuit: Circuit issue with the Driver Display Serial Communication circuit (instrument panel display).
• P0645 A/C Clutch Relay Control Circuit: Control circuit issue for the A/C clutch relay.
• P0646 A/C Clutch Relay Control Circuit Low: Low voltage in the A/C clutch relay control circuit.
• P0647 A/C Clutch Relay Control Circuit High: High voltage in the A/C clutch relay control circuit.
• P0648 Immobilizer Lamp Control Circuit: Control circuit issue for the immobilizer warning lamp.
• P0649 Cruise Control Lamp Control Circuit: Control circuit issue for the cruise control warning lamp.

P0650 – P0699: Malfunction Indicator Light (MIL), Sensor Reference Voltage B & C, Engine RPM/Hot Lamp, Fuel Level Output, Actuator Supply Voltage, Intake Manifold Tuning Valve, PCM/ECM/TCM Temperature Sensor, Glow Plug Module, ECM/PCM Power Relay, and Fan Control Issues

The final section of the P0600 series (P0650 to P0699) covers a very wide range of circuits and components, including the Malfunction Indicator Light (MIL), Sensor Reference Voltage B & C circuits, Engine RPM output, Engine Hot Lamp, Fuel Level Output, Actuator Supply Voltage circuits, Intake Manifold Tuning Valves, PCM/ECM/TCM Internal Temperature Sensors, Glow Plug Modules (diesel), ECM/PCM Power Relays, and Cooling Fan Control circuits.

• P0650 Malfunction Indicator Light Control Circuit: Control circuit issue for the Malfunction Indicator Light (MIL), also known as the Check Engine Light.
• P0651 Sensor Reference Voltage B Circuit/Open: Open circuit or malfunction in Sensor Reference Voltage B circuit (another sensor reference voltage supply).
• P0652 Sensor Reference Voltage B Circuit Low: Low voltage in Sensor Reference Voltage B circuit.
• P0653 Sensor Reference Voltage B Circuit High: High voltage in Sensor Reference Voltage B circuit.
• P0654 Engine RPM Output Circuit: Circuit issue with the Engine RPM Output circuit (tachometer signal).
• P0655 Engine Hot Lamp Output Control Circuit: Control circuit issue for the Engine Hot warning lamp (overheating indicator).
• P0656 Fuel level Output Circuit: Circuit issue with the Fuel Level Output circuit (fuel gauge signal).
• P0657 Actuator Supply Voltage A Circuit / Open: Open circuit or malfunction in Actuator Supply Voltage A circuit. This circuit provides power to various actuators.
• P0658 Actuator Supply Voltage A Circuit Low: Low voltage in Actuator Supply Voltage A circuit.
• P0659 Actuator Supply Voltage A Circuit High: High voltage in Actuator Supply Voltage A circuit.
• P0660 Intake Manifold Tuning Valve Control Circuit / Open – Bank 1: Open circuit in Intake Manifold Tuning Valve Control circuit on Bank 1 (if equipped with intake manifold tuning valves).
• P0661 Intake Manifold Tuning Valve Control Circuit Low – Bank 1: Low voltage in Intake Manifold Tuning Valve Control circuit on Bank 1.
• P0662 Intake Manifold Tuning Valve Control Circuit High – Bank 1: High voltage in Intake Manifold Tuning Valve Control circuit on Bank 1.
• (P0663 – P0665): These codes mirror P0660-P0662 but are for Bank 2 Intake Manifold Tuning Valve Control circuit, if equipped.
• P0666 PCM / ECM / TCM Internal Temperature Sensor Circuit: Circuit issue with the internal temperature sensor within the PCM, ECM, or TCM.
• P0667 PCM / ECM / TCM Internal Temperature Sensor Range/Performance: Performance issue with the PCM/ECM/TCM internal temperature sensor.
• P0668 PCM / ECM / TCM Internal Temperature Sensor Circuit Low: Low voltage from the PCM/ECM/TCM internal temperature sensor.
• P0669 PCM / ECM / TCM Internal Temperature Sensor Circuit High: High voltage from the PCM/ECM/TCM internal temperature sensor.
• P0670 Glow Plug Module Control Circuit: Control circuit issue for the Glow Plug Module (diesel engines, less relevant for gasoline 2001 Impala).
• (P0671 – P0682): These codes are for individual Cylinder Glow Plug Circuits 1 through 12 (diesel engines, less relevant for gasoline 2001 Impala), indicating circuit issues with specific glow plugs.
• P0683 Glow Plug Control Module to PCM Communication Circuit: Communication circuit issue between the Glow Plug Control Module and the PCM (diesel engines, less relevant for gasoline 2001 Impala).
• P0684 Glow Plug Control Module to PCM Communication Circuit Range/Performance: Performance issue in communication between Glow Plug Control Module and PCM.
• P0685 ECM/PCM Power Relay Control Circuit/Open: Open circuit in the ECM/PCM Power Relay Control circuit. This relay provides power to the ECM/PCM.
• P0686 ECM/PCM Power Relay Control Circuit Low: Low voltage in the ECM/PCM Power Relay Control circuit.
• P0687 ECM/PCM Power Relay Control Circuit High: High voltage in the ECM/PCM Power Relay Control circuit.
• P0688 ECM/PCM Power Relay Sense Circuit: Circuit issue with the ECM/PCM Power Relay Sense circuit (feedback circuit to monitor relay status).
• P0689 ECM/PCM Power Relay Sense Circuit Low: Low voltage in the ECM/PCM Power Relay Sense circuit.
• P0690 ECM/PCM Power Relay Sense Circuit High: High voltage in the ECM/PCM Power Relay Sense circuit.
• P0691 Fan 1 Control Circuit Low: Low voltage in Fan 1 control circuit (cooling fan).
• P0692 Fan 1 Control Circuit High: High voltage in Fan 1 control circuit.
• P0693 Fan 2 Control Circuit Low: Low voltage in Fan 2 control circuit.
• P0694 Fan 2 Control Circuit High: High voltage in Fan 2 control circuit.
• P0695 Fan 3 Control Circuit Low: Low voltage in Fan 3 control circuit.
• P0696 Fan 3 Control Circuit High: High voltage in Fan 3 control circuit.
• P0697 Sensor Reference Voltage C Circuit / Open: Open circuit or malfunction in Sensor Reference Voltage C circuit (another sensor reference voltage supply).
• P0698 Sensor Reference Voltage C Circuit Low: Low voltage in Sensor Reference Voltage C circuit.
• P0699 Sensor Reference Voltage C Circuit High: High voltage in Sensor Reference Voltage C circuit.

Decoding 2001 Chevy Impala OBD2 Codes: The P0700 Series

The P0700 series OBD2 codes for your 2001 Chevy Impala are primarily related to the Transmission Control System. These codes indicate problems within the automatic transmission, its sensors, solenoids, and overall operation. Transmission issues can significantly impact vehicle drivability and may lead to serious damage if not addressed promptly.

P0700 – P0709: Transmission Control System (General) & Range Sensor Issues

This range (P0700 to P0709) covers general Transmission Control System (TCS) malfunctions and Transmission Range Sensor (TRS) circuit problems.

• P0700 Transmission Control System (MIL Request): General Transmission Control System malfunction. This code itself doesn’t pinpoint a specific issue but indicates that the TCM has detected a problem and is requesting the Malfunction Indicator Light (MIL) to illuminate. It’s often accompanied by other more specific P07xx codes.
• P0701 Transmission Control System Range/Performance: Performance issue within the Transmission Control System.
• P0702 Transmission Control System Electrical: Electrical problem within the Transmission Control System.
• P0703 Brake Switch B Input Circuit: Malfunction in the Brake Switch B Input circuit. This circuit provides a signal from a second brake switch (often redundant for safety).
• P0704 Clutch Switch Input Circuit: Malfunction in the Clutch Switch Input circuit (manual transmissions only, less relevant for typical 2001 Impala automatics).
• P0705 Transmission Range Sensor A Circuit (PRNDL Input): Malfunction in Transmission Range Sensor A circuit. The TRS (also known as Neutral Safety Switch or Park/Neutral Position switch) indicates the selected gear position (Park, Reverse, Neutral, Drive, Low).
• P0706 Transmission Range Sensor A Circuit Range/Performance: Performance issue with Transmission Range Sensor A circuit.
• P0707 Transmission Range Sensor A Circuit Low Input: Low input signal from Transmission Range Sensor A circuit.
• P0708 Transmission Range Sensor A Circuit High Input: High input signal from Transmission Range Sensor A circuit.
• P0709 Transmission Range Sensor A Circuit Intermittent: Intermittent signal from Transmission Range Sensor A circuit.

P0710 – P0728: Transmission Fluid Temperature, Turbine/Input Shaft Speed, and Engine Speed Input Issues

Codes P0710 through P0728 address Transmission Fluid Temperature (TFT) sensor problems, Turbine/Input Shaft Speed Sensor issues, and Engine Speed Input Circuit malfunctions related to the transmission.

• P0710 Transmission Fluid Temperature Sensor A Circuit: Malfunction in Transmission Fluid Temperature Sensor A circuit. The TFT sensor measures the temperature of the transmission fluid, which is crucial for transmission control and preventing overheating.
• P0711 Transmission Fluid Temperature Sensor A Circuit Range/Performance: Performance issue with TFT Sensor A circuit.
• P0712 Transmission Fluid Temperature Sensor A Circuit Low Input: Low input signal from TFT Sensor A, indicating a low-temperature reading (or sensor fault).
• P0713 Transmission Fluid Temperature Sensor A Circuit High Input: High input signal, suggesting a high-temperature reading (or sensor fault).
• P0714 Transmission Fluid Temperature Sensor A Circuit Intermittent: Intermittent signal from TFT Sensor A circuit.
• P0715 Turbine/Input Shaft Speed SensorA Circuit: Malfunction in Turbine/Input Shaft Speed Sensor A circuit. This sensor measures the speed of the transmission input shaft (turbine shaft), which is used for shift control and torque converter clutch operation.
• P0716 Turbine/Input Shaft Speed Sensor A Circuit Range/Performance: Performance issue with Turbine/Input Shaft Speed Sensor A circuit.
• P0717 Turbine/Input Shaft Speed Sensor A Circuit No Signal: No signal from Turbine/Input Shaft Speed Sensor A circuit.
• P0718 Turbine/Input Shaft Speed Sensor A Circuit Intermittent: Intermittent signal from Turbine/Input Shaft Speed Sensor A circuit.
• P0719 Brake Switch B Input Circuit Low: Low input signal from Brake Switch B Input circuit.
• P0720 Output Shaft Speed Sensor Circuit: Malfunction in the Output Shaft Speed Sensor circuit. This sensor measures the speed of the transmission output shaft, used for vehicle speed calculation and shift control.
• P0721 Output Shaft Speed Sensor Circuit Range/Performance: Performance issue with Output Shaft Speed Sensor circuit.
• P0722 Output Shaft Speed Sensor Circuit No Signal: No signal from Output Shaft Speed Sensor circuit.
• P0723 Output Shaft Speed Sensor Circuit Intermittent: Intermittent signal from Output Shaft Speed Sensor circuit.
• P0724 Brake Switch B Input Circuit High: High input signal from Brake Switch B Input circuit.
• P0725 Engine Speed Input Circuit: Malfunction in the Engine Speed Input Circuit to the TCM. The TCM needs engine speed information for proper transmission control.
• P0726 Engine Speed Input Circuit Range/Performance: Performance issue with Engine Speed Input Circuit to the TCM.
• P0727 Engine Speed Input Circuit No Signal: No signal from Engine Speed Input Circuit to the TCM.
• P0728 Engine Speed Input Circuit Intermittent: Intermittent signal from Engine Speed Input Circuit to the TCM.

P0729 – P0749: Gear Ratio Errors, Torque Converter Clutch Solenoid, and Pressure Control Solenoid A Issues

Codes P0729 through P0749 address Incorrect Gear Ratio errors, Torque Converter Clutch (TCC) Solenoid circuit problems, and Pressure Control Solenoid A malfunctions.

• P0729 Gear 6 Incorrect Ratio: Incorrect gear ratio detected in 6th gear (if applicable, some 2001 Impalas may not have 6-speed transmissions).
• P0730 Incorrect Gear Ratio: General Incorrect Gear Ratio detected. This code indicates that the TCM has detected a mismatch between engine speed, input shaft speed, and output shaft speed, suggesting a gear slippage or mechanical issue within the transmission.
• (P0731 – P0736): These codes continue the pattern for Incorrect Gear Ratio in Gears 1 through 5 and Reverse, indicating gear ratio problems in specific gears.
• P0737 TCM Engine Speed Output Circuit: Circuit issue with TCM Engine Speed Output circuit (signal output from TCM to other modules).
• P0738 TCM Engine Speed Output Circuit Low: Low voltage in TCM Engine Speed Output circuit.
• P0739 TCM Engine Speed Output Circuit High: High voltage in TCM Engine Speed Output circuit.
• P0740 Torque Converter Clutch Solenoid Circuit / Open: Open circuit in the Torque Converter Clutch (TCC) Solenoid circuit. The TCC solenoid controls the engagement of the torque converter clutch, which improves fuel economy at highway speeds.
• P0741 Torque Converter Clutch Solenoid Circuit Performance Or Stuck Off: Performance issue with TCC Solenoid, or it’s stuck in the OFF position (not engaging the clutch).
• P0742 Torque Converter Clutch Solenoid Circuit Stuck On: TCC Solenoid is stuck in the ON position (clutch always engaged).
• P0743 Torque Converter Clutch Solenoid Circuit Electrical: Electrical problem in the TCC Solenoid circuit.
• P0744 Torque Converter Clutch Solenoid Circuit Intermittent: Intermittent issue in the TCC Solenoid circuit.
• P0745 Pressure Control Solenoid A: Malfunction in Pressure Control Solenoid A. Pressure control solenoids regulate hydraulic pressure within the transmission for shifting and clutch application.
• P0746 Pressure Control Solenoid A Performance or Stuck Off: Performance issue with Pressure Control Solenoid A, or it’s stuck in the OFF position (not applying pressure).
• P0747 Pressure Control Solenoid A Stuck On: Pressure Control Solenoid A is stuck in the ON position (always applying pressure).
• P0748 Pressure Control Solenoid A Electrical: Electrical problem in Pressure Control Solenoid A circuit.
• P0749 Pressure Control Solenoid A Intermittent: Intermittent issue with Pressure Control Solenoid A.

P0750 – P0779: Shift Solenoid A, B, C, D, E, and Pressure Control Solenoid B Issues

Codes P0750 through P0779 cover Shift Solenoid A, B, C, D, E, and Pressure Control Solenoid B malfunctions. Shift solenoids control the flow of hydraulic fluid to engage different gears in the automatic transmission.

• P0750 Shift Solenoid A: Malfunction in Shift Solenoid A circuit.
• P0751 Shift Solenoid A Performance or Stuck Off: Performance issue with Shift Solenoid A, or it’s stuck in the OFF position (not shifting correctly).
• P0752 Shift Solenoid A Stuck On: Shift Solenoid A is stuck in the ON position (always applying pressure).
• P0753 Shift Solenoid A Electrical: Electrical problem in Shift Solenoid A circuit.
• P0754 Shift Solenoid A Intermittent: Intermittent issue with Shift Solenoid A.
• (P0755 – P0759): These codes mirror P0750-P0754 but are for Shift Solenoid B, indicating similar malfunctions, performance issues, stuck conditions, electrical problems, and intermittent issues but for Shift Solenoid B.
• (P0760 – P0764): These codes mirror P0750-P0754 but are for Shift Solenoid C.
• (P0765 – P0769): These codes mirror P0750-P0754 but are for Shift Solenoid D.
• (P0770 – P0774): These codes mirror P0750-P0754 but are for Shift Solenoid E.
• P0775 Pressure Control Solenoid B: Malfunction in Pressure Control Solenoid B circuit.
• P0776 Pressure Control Solenoid B Performance or Stuck Off: Performance issue with Pressure Control Solenoid B, or it’s stuck in the OFF position.
• P0777 Pressure Control Solenoid B Stuck On: Pressure Control Solenoid B is stuck in the ON position.
• P0778 Pressure Control Solenoid B Electrical: Electrical problem in Pressure Control Solenoid B circuit.
• P0779 Pressure Control Solenoid B Intermittent: Intermittent issue with Pressure Control Solenoid B.

P0780 – P0799: Shift Malfunction, 1-2 to 4-5 Shift Issues, Shift/Timing Solenoid, Normal/Performance Switch, Intermediate Shaft Speed, and Pressure Control Solenoid C Issues

The final section of the P0700 series (P0780 to P0799) covers Shift Malfunction codes, specific gear shift issues (1-2 to 4-5), Shift/Timing Solenoid problems, Normal/Performance Switch circuit malfunctions, Intermediate Shaft Speed Sensor issues, and Pressure Control Solenoid C malfunctions.

• P0780 Shift Malfunction: General Shift Malfunction detected. This is a broad code indicating a problem with the transmission’s ability to shift gears correctly.
• (P0781 – P0784): These codes are for specific gear shift malfunctions (1-2 Shift, 2-3 Shift, 3-4 Shift, 4-5 Shift), indicating problems during specific gear changes.
• P0785 Shift/Timing Solenoid: Malfunction in Shift/Timing Solenoid circuit.
• P0786 Shift/Timing Solenoid Range/Performance: Performance issue with Shift/Timing Solenoid circuit.
• P0787 Shift/Timing Solenoid Low: Low voltage in Shift/Timing Solenoid circuit.
• P0788 Shift/Timing Solenoid High: High voltage in Shift/Timing Solenoid circuit.
• P0789 Shift/Timing Solenoid Intermittent: Intermittent issue with Shift/Timing Solenoid.
• P0790 Normal/Performance Switch Circuit: Malfunction in the Normal/Performance Switch circuit (if equipped, allows driver to select different shift modes).
• P0791 Intermediate Shaft Speed Sensor A Circuit: Malfunction in Intermediate Shaft Speed Sensor A circuit. This sensor measures the speed of an intermediate shaft within the transmission.
• P0792 Intermediate Shaft Speed Sensor A Circuit Range/Performance: Performance issue with Intermediate Shaft Speed Sensor A circuit.
• P0793 Intermediate Shaft Speed Sensor A Circuit No Signal: No signal from Intermediate Shaft Speed Sensor A circuit.
• P0794 Intermediate Shaft Speed Sensor A Circuit Intermittent: Intermittent signal from Intermediate Shaft Speed Sensor A circuit.
• P0795 Pressure Control Solenoid C: Malfunction in Pressure Control Solenoid C circuit.
• P0796 Pressure Control Solenoid C Performance or Stuck Off: Performance issue with Pressure Control Solenoid C, or it’s stuck in the OFF position.
• P0797 Pressure Control Solenoid C Stuck On: Pressure Control Solenoid C is stuck in the ON position.
• P0798 Pressure Control Solenoid C Electrical: Electrical problem in Pressure Control Solenoid C circuit.
• P0799 Pressure Control Solenoid C Intermittent: Intermittent issue with Pressure Control Solenoid C.

Decoding 2001 Chevy Impala OBD2 Codes: P0800 – P0999 Series and Beyond

The OBD2 code list extends beyond the P0700 series. While the P0800 and P0900 series are less commonly encountered for typical 2001 Chevy Impala issues, understanding their general categories can still be helpful. These series delve into more specialized systems, including:

• P0800 Series: Transfer Case Control System (for 4WD/AWD vehicles, less relevant for standard Impala), Clutch Position Sensors, Gear Lever Position Sensors, Four-Wheel Drive (4WD) Switch Circuits, Transmission Fluid Pressure Sensors/Switches, Park/Neutral Switch, Traction Control Input, Gear Shift Module Communication, TCM Communication, and Transmission Fluid Pressure issues.
• P0900 Series: Clutch Actuator Circuits (manual transmissions, less relevant), Gate Select/Gear Shift Position Circuits (automated manual transmissions, less relevant), Gear Shift Actuator Circuits, Hydraulic Pressure Sensors/Units/Pumps (automated manual transmissions, less relevant), Auto Shift Manual Control Circuits (automated manual transmissions, less relevant), and Pressure Control Solenoid Control Circuits (further transmission pressure control codes).
• P0A00 – P0FFF Series: These code ranges are primarily reserved for Hybrid Powertrain Control Systems and more advanced or manufacturer-specific codes, and are generally not applicable to a standard 2001 Chevy Impala unless it has been heavily modified with hybrid or electric components.

Important Note: This extensive list provides a general overview of OBD2 codes that could be relevant to a 2001 Chevy Impala. However, for precise diagnosis, always:

1. Use an OBD2 Scanner: Get a code reader to confirm the exact code(s) your vehicle is displaying.
2. Consult a Repair Manual: Refer to a repair manual specific to a 2001 Chevy Impala for detailed troubleshooting steps and procedures for each code.
3. Seek Professional Help: If you are not comfortable diagnosing or repairing vehicle issues, consult a qualified mechanic. They have the expertise and tools to accurately diagnose and fix the problem indicated by the OBD2 codes.

Conclusion: Using OBD2 Codes to Maintain Your 2001 Chevy Impala

OBD2 codes are a powerful diagnostic tool for your 2001 Chevy Impala. By understanding these codes, you can take a proactive approach to vehicle maintenance, address issues early, and potentially prevent more costly repairs down the road.

Remember, this guide provides a comprehensive overview. When your check engine light comes on, the first step is always to retrieve the specific OBD2 code. Use this guide as a starting point for understanding the potential problem area, but always follow up with thorough diagnosis and appropriate repair procedures.

Keeping your 2001 Chevy Impala running smoothly and efficiently is easier with the knowledge of OBD2 codes at your fingertips. Use this resource wisely, and don’t hesitate to seek professional help when needed to keep your vehicle in top condition for years to come.