2003 Protege OBD2 Codes: Your Guide to Decoding Engine Trouble

Navigating car troubles can be stressful, especially when the check engine light illuminates in your 2003 Mazda Protege. Understanding the OBD2 system and its diagnostic trouble codes is the first step to resolving these issues efficiently. This guide provides a comprehensive list of Mazda-specific OBD2 codes relevant to your 2003 Protege, helping you understand what these codes mean and potentially diagnose the problem.

The On-Board Diagnostics II (OBD2) system is a standardized system in most vehicles, including the 2003 Mazda Protege, designed to monitor various engine and emission control systems. When the system detects a problem, it triggers the check engine light and stores a Diagnostic Trouble Code (DTC). These codes are invaluable for mechanics and car owners alike in pinpointing the source of the issue.

This article delves into Mazda-specific P-codes, which are powertrain codes that relate to the engine, transmission, and related components. While generic OBD2 codes are universal across car brands, manufacturers like Mazda also have their own set of enhanced codes to provide more detailed diagnostics. Understanding these codes specific to Mazda can significantly aid in diagnosing problems in your 2003 Protege.

Below is an extensive list of Mazda-specific OBD2 codes that may be applicable to your 2003 Protege. Please note that while this list is comprehensive, it’s always recommended to consult your 2003 Mazda Protege repair manual and a professional mechanic for accurate diagnosis and repair.

Mazda Specific OBD2 Codes for 2003 Protege

• P1000 – OBD II Monitor Testing Not Completed: This code indicates that the OBD-II system self-tests have not been fully completed. This is often seen after a battery disconnect or clearing codes and usually resolves itself after a drive cycle.

• P1001 – Unable to Achieve Self-Test Function or SCP Error: Indicates a failure in the self-test function of the OBD-II system or a Serial Communication Protocol (SCP) error, pointing to potential communication issues within the vehicle’s computer network.

• P1100 – Mass Airflow Sensor Circuit Intermittent: Signifies an intermittent fault in the Mass Air Flow (MAF) sensor circuit. The MAF sensor measures the amount of air entering the engine, and a faulty circuit can lead to inaccurate readings.

• P1101 – Mass Airflow Sensor Circuit out of Self-Test Range: Suggests the MAF sensor circuit is operating outside the expected range during the self-test, possibly indicating a sensor malfunction or wiring problem.

• P1102 – Mass Airflow Sensor Signal Inconsistent with Throttle Position Sensor: This code appears when the signal from the MAF sensor doesn’t correlate with the Throttle Position Sensor (TPS) signal. This inconsistency can point to issues with either sensor or vacuum leaks.

• P1103 – Mass Airflow Sensor Signal Inconsistent with Engine Speed: Similar to P1102, this code highlights an inconsistency, but this time between the MAF sensor signal and engine speed. It could indicate a faulty MAF sensor, vacuum leak, or engine speed sensor issue.

• P1110 – Intake Air Temperature Sensor Signal (Dynamic Chamber) Circuit: Indicates a problem in the Intake Air Temperature (IAT) sensor circuit specifically for a dynamic chamber (if applicable to the 2003 Protege – some systems have dual IATs).

• P1112 – Intake Air Temperature Sensor Circuit Intermittent: Points to an intermittent fault in the IAT sensor circuit. An unreliable IAT signal can affect fuel mixture and engine performance.

• P1113 – Intake Air Temperature Sensor Signal (Dynamic Chamber) Circuit (Redundant): Similar to P1110 but might refer to a redundant IAT sensor in systems that utilize one.

• P1114 – Intake Air Temperature Sensor Circuit Low Input: Indicates the IAT sensor is sending a low voltage signal, which could be due to a short to ground, a faulty sensor, or wiring issues.

• P1116 – ECT Sensor Circuit Out of Self Test Range: Engine Coolant Temperature (ECT) sensor circuit is out of the expected range during self-test. A malfunctioning ECT sensor can cause incorrect temperature readings affecting engine control.

• P1117 – ECT Sensor Signal Intermittent: Intermittent signal from the ECT sensor circuit, leading to potentially erratic engine temperature readings and control.

• P1120 – Throttle Position Sensor out of Range Low: The Throttle Position Sensor (TPS) signal is below the expected range. This could be due to a TPS malfunction, wiring issues, or throttle body problems.

• P1121 – Throttle Position Sensor Signal Not Consistent with Mass Airflow Signal: Similar to P1102, but specifically points to the TPS signal being inconsistent with the MAF sensor signal.

• P1122 – Throttle Position Stuck Closed: Indicates the TPS is reporting a closed throttle position even when it should be open. This can cause severe drivability issues.

• P1123 – Throttle Position Stuck Open: Conversely, this code suggests the TPS is reporting an open throttle position when it should be closed, also leading to drivability problems.

• P1124 – Throttle Position Sensor Signal Out of Self Test Range: TPS signal is outside the acceptable range during self-test, indicating a potential sensor or circuit problem.

• P1125 – Throttle Position Sensor Signal Intermittent: Intermittent signal from the TPS, causing potentially unstable throttle control and engine performance.

• P1127 – HO2S Bank 1 Sensor 2 Heater Not On During Key On Engine Running Self Test: Heated Oxygen Sensor (HO2S) Bank 1 Sensor 2 heater is not activating during the self-test. The heater is crucial for the sensor to reach operating temperature quickly for accurate readings.

• P1128 – HO2S Bank 1 Sensor 1 Signals Swapped in Key On Engine Running Self Test: Indicates that the signals from HO2S Bank 1 Sensor 1 might be swapped, possibly due to wiring errors.

• P1130 – HO2S Bank 1 Sensor 1 Not Switching (Fuel Control Limit Reached): HO2S Bank 1 Sensor 1 is not switching as expected, and the fuel control system has reached its limit trying to compensate, potentially indicating a rich or lean condition beyond normal adjustment.

• P1131 – HO2S Bank 1 Sensor 1 Signal Below 0.45v (A/F Ratio Too Lean): HO2S Bank 1 Sensor 1 is detecting a lean air-fuel ratio (too much oxygen). This can be caused by vacuum leaks, lean fuel injectors, or a faulty sensor.

• P1132 – HO2S Bank 1 Sensor 1 Signal Above 0.45v (A/F Ratio Too Rich): HO2S Bank 1 Sensor 1 is detecting a rich air-fuel ratio (too much fuel). Possible causes include faulty fuel injectors, high fuel pressure, or a faulty sensor.

• P1135 – HO2S Bank 1 Sensor 1 Heater Circuit Low Input: Low voltage detected in the heater circuit of HO2S Bank 1 Sensor 1, potentially due to wiring issues or a failing heater element.

• P1136 – HO2S Bank 1 Sensor 1 Heater Circuit High Input: High voltage detected in the heater circuit of HO2S Bank 1 Sensor 1, possibly caused by a short circuit or wiring problem.

• P1137 – HO2S Bank 1 Sensor 2 Not Switching (Fuel Control Limit Reached): Similar to P1130, but for HO2S Bank 1 Sensor 2 (downstream sensor).

• P1138 – HO2S Bank 1 Sensor 2 Signal Above 0.45v (A/F Ratio Too Rich): Similar to P1132, but for HO2S Bank 1 Sensor 2.

• P1141 – HO2S Bank 1 Sensor 2 Heater Circuit Low Input: Low voltage in the heater circuit of HO2S Bank 1 Sensor 2.

• P1142 – HO2S Bank 1 Sensor 2 Heater Circuit High Input: High voltage in the heater circuit of HO2S Bank 1 Sensor 2.

• P1143 – HO2S Bank 1 Sensor 3 Signal Below 0.45v (A/F Ratio Too Lean): Applies to systems with a third oxygen sensor (if equipped, unlikely on a 2003 Protege typically), indicating a lean condition.

• P1144 – HO2S Bank 1 Sensor 3 Signal Above 0.45v (A/F Ratio Too Rich): Applies to systems with a third oxygen sensor, indicating a rich condition.

• P1150 – HO2S Bank 2 Sensor 1 Not Switching (Fuel Control Limit Reached): Similar to P1130, but for HO2S Bank 2 Sensor 1 (if applicable to the 2003 Protege – likely only on V-engines).

• P1151 – HO2S Bank 2 Sensor 1 Signal Below 0.45v (A/F Ratio Too Lean): Similar to P1131, but for HO2S Bank 2 Sensor 1.

• P1152 – HO2S Bank 2 Sensor 1 Signal Above 0.45v (A/F Ratio Too Rich): Similar to P1132, but for HO2S Bank 2 Sensor 1.

• P1169 – HO2S Bank 1 Sensor 1 Circuit Fixed (Bank 1 Sensor 1): Indicates a fixed or stuck signal from HO2S Bank 1 Sensor 1, meaning it’s not responding to changes in exhaust gas composition.

• P1170 – HO2S Bank 1 Sensor 1 Circuit Fixed (Bank 1 Sensor 1) – Redundant code likely similar to P1169.

• P1173 – HO2S Bank 2 Sensor 1 Circuit Fixed (Bank 2 Sensor 1): Similar to P1169, but for HO2S Bank 2 Sensor 1.

• P1195 – EGR Boost Sensor Circuit: Problem in the Exhaust Gas Recirculation (EGR) boost sensor circuit. The EGR system reduces NOx emissions, and a faulty sensor can affect its operation.

• P1196 – Ignition Switch Start Circuit: Fault in the ignition switch start circuit, potentially affecting the starting system of the vehicle.

• P1235 – Fuel Pump Control Circuit: Issue with the fuel pump control circuit. This is critical as the fuel pump delivers fuel to the engine.

• P1236 – Fuel Pump Control Out Range: Fuel pump control circuit is operating outside the expected range, possibly indicating a pump, relay, or wiring problem.

• P1250 – Pressure Regulator Control Solenoid Circuit: Problem in the pressure regulator control solenoid circuit. This solenoid controls fuel pressure, and a fault can affect fuel delivery.

• P1252 – Pressure Regulator Control Solenoid ‘2’ Circuit: Similar to P1250, but might refer to a secondary pressure regulator solenoid in some systems.

• P1260 – Anti-Theft System Signal Detected – Engine Disabled: The anti-theft system has detected an issue and has disabled the engine. This often requires professional intervention to reset the system.

• P1270 – Engine RPM or Vehicle Speed Limit Reached: Indicates that the engine RPM or vehicle speed limiter has been reached. This might be normal under certain driving conditions, but persistent codes might indicate a limiter malfunction.

• P1309 – Misfire Detection Monitor: Fault in the misfire detection monitoring system itself. This system identifies engine misfires, so a fault here can prevent accurate misfire detection.

• P1345 – No CMP or SGC Signal: No signal from either the Camshaft Position (CMP) sensor or Sync Generator Circuit (SGC). These sensors are crucial for engine timing and fuel injection.

• P1351 – Ignition Diagnostic Monitor Signal Lost to PCM or Out Of Range: Signal from the Ignition Diagnostic Monitor is lost or out of range to the Powertrain Control Module (PCM). This monitor helps the PCM control ignition timing and detect ignition problems.

• P1352 – Ignition Coil ‘A’ Primary Circuit: Problem in the primary circuit of ignition coil ‘A’. Coil ‘A’ refers to a specific coil in the ignition system.

• P1353 – Ignition Coil ‘B’ Primary Circuit: Problem in the primary circuit of ignition coil ‘B’.

• P1354 – Ignition Coil ‘C’ Primary Circuit: Problem in the primary circuit of ignition coil ‘C’.

• P1358 – Ignition Diagnostic Monitor Signal Out Of Self Test Range: The Ignition Diagnostic Monitor signal is out of the expected range during self-test.

• P1359 – SPOUT Signal Lost To Powertrain Control Module Or Out Of Range: Spark Output (SPOUT) signal is lost or out of range to the PCM. The SPOUT signal controls ignition timing advance.

• P1360 – Ignition Coil ‘A’ Secondary Circuit: Problem in the secondary circuit of ignition coil ‘A’.

• P1361 – Ignition Coil ‘B’ Secondary Circuit: Problem in the secondary circuit of ignition coil ‘B’.

• P1362 – Ignition Coil ‘C’ Secondary Circuit: Problem in the secondary circuit of ignition coil ‘C’.

• P1364 – Ignition Coil Primary Circuit – Generic code, potentially for issues across multiple primary coil circuits.

• P1365 – Ignition Coil Secondary Circuit – Generic code, potentially for issues across multiple secondary coil circuits.

• P1390 – Octane Adjust Shorting Bar Out or Circuit Open: The octane adjust shorting bar circuit is open or not properly connected. This circuit allows for adjustment based on fuel octane rating, though often fixed in modern cars.

• P1400 – DPFE Sensor Circuit Low Input: Differential Pressure Feedback EGR (DPFE) sensor circuit is showing low input. The DPFE sensor measures EGR flow, and a low input might indicate a sensor or wiring problem.

• P1401 – DPFE Sensor Circuit High Input: DPFE sensor circuit is showing high input, potentially indicating a sensor or wiring issue.

• P1402 – EGR Valve Position Sensor Circuit: Problem in the EGR valve position sensor circuit. This sensor provides feedback on the EGR valve’s position to the PCM.

• P1405 – DPFE Sensor Upstream Hose Off Or Plugged: The upstream hose of the DPFE sensor is either off or plugged, preventing accurate EGR flow measurement.

• P1406 – DPFE Sensor Downstream Hose Off or Plugged: The downstream hose of the DPFE sensor is off or plugged.

• P1407 – No EGR Flow Detected: The system is not detecting EGR flow when it’s expected, which could be due to a blocked EGR passage, faulty valve, or sensor issues.

• P1408 – EGR System Flow Out of Key On Engine Running Self Test Range: EGR flow is outside the expected range during the self-test.

• P1409 – EGR Vacuum Regulator Solenoid Circuit: Problem in the EGR vacuum regulator solenoid circuit. This solenoid controls vacuum to the EGR valve.

• P1410 – EGR Boost Solenoid Valve Stuck: The EGR boost solenoid valve is stuck, potentially affecting EGR system operation.

• P1443 – EVAP System Purge Flow Fault: Fault in the Evaporative Emission Control (EVAP) system purge flow. The EVAP system prevents fuel vapor from escaping into the atmosphere.

• P1444 – EVAP Purge Flow Sensor Circuit Low Voltage: Low voltage in the EVAP purge flow sensor circuit.

• P1446 – EVAP Purge Flow Sensor Circuit High Voltage: High voltage in the EVAP purge flow sensor circuit.

• P1449 – CDCV or Throttle PositionCV Circuit: Circuit issue with either the Canister Duty Cycle Valve (CDCV) or Throttle Position CV (likely related to throttle control).

• P1450 – EVAP Control System Fault: General fault within the EVAP control system.

• P1451 – Canister Vent Solenoid Circuit: Problem in the canister vent solenoid circuit. This solenoid controls venting of the EVAP canister.

• P1455 – Fuel Tank Level Sensor Circuit: Issue with the fuel tank level sensor circuit, potentially affecting fuel gauge readings.

• P1460 – Wide Open Throttle A/C Cut-Off Relay Circuit: Fault in the Wide Open Throttle (WOT) A/C cut-off relay circuit. This circuit disables the A/C compressor during WOT for maximum engine power.

• P1464 – Air Conditioning Control Signal Circuit: Problem in the air conditioning control signal circuit.

• P1474 – Fan Control (Primary Winding) Circuit: Fault in the primary winding circuit of the cooling fan control system.

• P1479 – Fan Control (Condenser Primary) Circuit: Fault in the primary winding circuit of the condenser fan control system.

• P1485 – EGR Vacuum Solenoid Circuit: Redundant code, similar to P1409.

• P1486 – EGR Vent Solenoid Circuit: Problem in the EGR vent solenoid circuit.

• P1487 – EGR-CHK (Boost) Solenoid Circuit: Problem in the EGR-CHK (boost) solenoid circuit, possibly related to EGR boost control.

• P1496 – EGR Valve Motor Coil ‘1’ Open or Shorted: Open or short circuit in coil ‘1’ of the EGR valve motor (for EGR valves using a motor).

• P1497 – EGR Valve Motor Coil ‘2’ Open or Shorted: Open or short circuit in coil ‘2’ of the EGR valve motor.

• P1498 – EGR Valve Motor Coil ‘3 Open or Shorted: Open or short circuit in coil ‘3’ of the EGR valve motor.

• P1499 – EGR Valve Motor Coil ‘4’ Open or Shorted: Open or short circuit in coil ‘4’ of the EGR valve motor.

• P1500 – Vehicle Speed Sensor Intermittent Signal: Intermittent signal from the Vehicle Speed Sensor (VSS). The VSS provides speed information to the PCM and other systems.

• P1501 – Vehicle Speed Sensor Out of Self Test Range: VSS signal is out of range during self-test.

• P1502 – Vehicle Speed Sensor Circuit Error: General error in the VSS circuit.

• P1504 – Idle Air Control Solenoid Circuit Intermittent: Intermittent fault in the Idle Air Control (IAC) solenoid circuit. The IAC valve controls idle speed.

• P1505 – Idle Air Control System at Adaptive Clip: The IAC system has reached its adaptive limit, suggesting a problem with idle control, possibly due to vacuum leaks or throttle body issues.

• P1506 – Idle Air Control System Overspeed Detected: Engine idle speed is higher than expected, potentially due to a faulty IAC valve or vacuum leak.

• P1507 – Idle Air Control System Underspeed Detected: Engine idle speed is lower than expected, possibly due to a faulty IAC valve, vacuum leak, or engine load issues.

• P1508 – Bypass Air Solenoid ‘1’ Circuit: Problem in the bypass air solenoid ‘1’ circuit. This solenoid might be part of the intake air control system.

• P1509 – Bypass Air Solenoid ‘2 Circuit: Problem in the bypass air solenoid ‘2’ circuit.

• P1512 – VTCS Fault: Variable Tumble Control System (VTCS) fault. The VTCS optimizes intake air swirl for better combustion.

• P1521 – VRIS Solenoid ‘1’ Circuit: Variable Resonance Induction System (VRIS) solenoid ‘1’ circuit problem. VRIS optimizes intake manifold resonance for improved performance at different engine speeds.

• P1522 – VRIS Solenoid ‘2 Circuit: VRIS solenoid ‘2’ circuit problem.

• P1523 – VICS Solenoid Circuit: Variable Intake Control System (VICS) solenoid circuit problem – similar function to VRIS/VTCS.

• P1524 – Charge Air Cooler Bypass Solenoid Circuit: Problem in the charge air cooler bypass solenoid circuit (if the 2003 Protege has a turbo/supercharger and intercooler system, which is unlikely for standard models).

• P1525 – ABV Vacuum Solenoid Circuit: Air Bypass Valve (ABV) vacuum solenoid circuit problem (likely related to turbo/supercharger systems).

• P1526 – ABV Vent Solenoid Circuit: ABV vent solenoid circuit problem.

• P1529 – L/C Atmospheric Balance Air Control Valve Circuit: Lean Cruise (L/C) atmospheric balance air control valve circuit problem – related to lean burn strategies for fuel efficiency.

• P1540 – ABV System Fault: General fault within the ABV system.

• P1562 – Powertrain Control Module +BB Voltage Low: Low voltage detected at the Powertrain Control Module (PCM) +BB power supply, indicating a power supply issue to the PCM.

• P1569 – VTCS Circuit Low Input: Low input signal from the VTCS circuit.

• P1570 – VTCS Circuit High Input: High input signal from the VTCS circuit.

• P1601 – Powertrain Control Module Communication Line to TCM Error: Communication error between the PCM and Transmission Control Module (TCM).

• P1602 – Powertrain Control Module Communication Line to TCM Error – Redundant code, similar to P1601.

• P1602 – Immobilizer System Communication Error with Powertrain Control Module: Communication error between the immobilizer system and the PCM. This can prevent the engine from starting.

• P1603 – Immobilizer System Fault: General fault within the immobilizer system.

• P1604 – Immobilizer System Fault – Redundant code, similar to P1603.

• P1605 – Powertrain Control Module Keep Alive Memory Test Error: Error in the PCM’s Keep Alive Memory (KAM) test. KAM stores learned data, and an error can indicate PCM issues.

• P1608 – Powertrain Control Module (ECM CPU) DTC Test Fault: Fault in the PCM’s Engine Control Module (ECM) CPU DTC test, indicating a potential PCM internal problem.

• P1609 – Powertrain Control Module (ECM CPU) Knock Sensor Circuit: Fault in the PCM’s ECM CPU related to the knock sensor circuit.

• P1621 – lmmobilizer System Fault – Typo in original list, likely “Immobilizer System Fault”.

• P1622 – lmmobilizer System Fault – Typo in original list, likely “Immobilizer System Fault”.

• P1623 – lmmobilizer System Fault – Typo in original list, likely “Immobilizer System Fault”.

• P1624 – lmmobilizer System Fault – Typo in original list, likely “Immobilizer System Fault”.

• P1627 – Powertrain Control Module (ECM/TCS) Line Communication Error: Communication error on the line between the PCM (ECM) and Traction Control System (TCS).

• P1628 – Powertrain Control Module (ECM/TCS) Any Line Communication Error: General communication error on any line between the PCM (ECM) and TCS.

• P1631 – Generator Output Voltage Signal (No Output): No output voltage signal from the generator (alternator), meaning the charging system is not working.

• P1632 – Battery Voltage Monitor Circuit: Problem in the battery voltage monitor circuit.

• P1633 – Battery Overcharge Fault: Battery overcharge condition detected, potentially damaging the battery and electrical system.

• P1634 – Generator Terminal ‘B’ Circuit Open: Open circuit in the generator (alternator) terminal ‘B’ circuit, which is a main output terminal.

• P1650 – Power Steering Pressure Switch Out of Range Fault: Power Steering Pressure (PSP) switch signal is out of range. The PSP switch informs the PCM about power steering load.

• P1651 – Power Steering Pressure Switch Circuit: Problem in the PSP switch circuit.

• P1652 – Power Steering Pressure Switch Circuit – Redundant code, similar to P1651.

• P1701 – Transmission Range Sensor Reverse Engagement Error: Transmission Range Sensor is indicating a reverse engagement error, possibly during shifting into reverse.

• P1702 – Transmission Range Sensor Circuit Intermittent: Intermittent signal from the Transmission Range Sensor, which indicates the selected gear.

• P1703 – Brake On/Off Switch Out of Self Test Range: Brake On/Off switch signal is out of range during self-test. This switch is used by the transmission and cruise control systems.

• P1705 – Transmission Range Sensor out of Self Test Range: Transmission Range Sensor signal is out of range during self-test.

• P1709 – Clutch Pedal Position Switch Circuit: Problem in the clutch pedal position switch circuit (relevant for manual transmissions, if applicable to the 2003 Protege configuration being considered).

• P1711 – Transmission Fluid Temperature Sensor Circuit out of Self Test Range: Transmission Fluid Temperature (TFT) sensor signal is out of range during self-test.

• P1713 – Transmission Fluid Temperature Sensor Circuit: Problem in the TFT sensor circuit.

• P1714 – Shift Solenoid ‘1’ Mechanical Fault: Mechanical fault with shift solenoid ‘1’ in the transmission. Shift solenoids control gear changes in automatic transmissions.

• P1715 – Shift Solenoid ‘2’ Mechanical Fault: Mechanical fault with shift solenoid ‘2’.

• P1716 – Shift Solenoid ‘3’ Mechanical Fault: Mechanical fault with shift solenoid ‘3’.

• P1717 – Shift Solenoid ‘4’ Mechanical Fault: Mechanical fault with shift solenoid ‘4’.

• P1718 – Transmission Fluid Temperature Sensor Circuit – Redundant code, similar to P1713.

• P1720 – Vehicle Speed Sensor ‘2’ Signal Error: Error in the signal from Vehicle Speed Sensor ‘2’ (if equipped with a secondary VSS, potentially for ABS/Traction control).

• P1729 – Transmission 4×4 Low Switch Error: Error in the 4×4 low switch circuit (not applicable to standard front-wheel drive 2003 Protege models).

• P1740 – Torque Converter Clutch Solenoid Mechanical Fault: Mechanical fault with the Torque Converter Clutch (TCC) solenoid. The TCC solenoid controls the torque converter lock-up function.

• P1741 – Torque Converter Clutch Control Electrical Fault: Electrical fault in the TCC control circuit.

• P1742 – Torque Converter Clutch Solenoid Shorted: Short circuit in the TCC solenoid.

• P1743 – Torque Converter Clutch Failed On – TCIL is On: Torque Converter Clutch is stuck in the ‘on’ (locked) position, and the Transmission Control Indicator Lamp (TCIL) is illuminated.

• P1744 – Torque Converter Clutch Solenoid Mechanical Fault – Redundant code, similar to P1740.

• P1746 – Electronic Pressure Control Solenoid Circuit Open: Open circuit in the Electronic Pressure Control (EPC) solenoid circuit. The EPC solenoid controls transmission fluid pressure.

• P1747 – Electronic Pressure Control Solenoid Circuit – General fault in the EPC solenoid circuit.

• P1749 – Electronic Pressure Control Solenoid Circuit Low: Low voltage in the EPC solenoid circuit.

• P1751 – Transmission Shift Solenoid ‘A’ Mechanical Fault: Mechanical fault with transmission shift solenoid ‘A’ (could be equivalent to Shift Solenoid ‘1’).

• P1752 – Transmission Shift Solenoid ‘A’ Circuit Shorted: Short circuit in transmission shift solenoid ‘A’ circuit.

• P1754 – Transmission Coast Clutch Solenoid Electrical Fault: Electrical fault in the transmission coast clutch solenoid circuit (related to specific automatic transmission functions).

• P1756 – Transmission Shift Solenoid ‘B’ Mechanical Fault: Mechanical fault with transmission shift solenoid ‘B’ (could be equivalent to Shift Solenoid ‘2’).

• P1757 – Transmission Shift Solenoid ‘B’ Circuit Shorted: Short circuit in transmission shift solenoid ‘B’ circuit.

• P1761 – Transmission Shift Solenoid ‘3’ Mechanical Fault – Redundant code, similar to P1716.

• P1762 – Transmission SS3/SS4/OD Band Fault: Fault related to the transmission SS3/SS4/Overdrive (OD) band, indicating a mechanical issue within the transmission.

• P1765 – Transmission 3-2 Timing Solenoid Valve: Problem with the 3-2 timing solenoid valve in the transmission, which controls timing during 3-2 downshifts.

• P1767 – Torque Converter Clutch Solenoid Circuit – Redundant code, similar to P1741.

• P1771 – Throttle Position Sensor Circuit Open to Transmission Control Module: Open circuit in the TPS signal wire going to the TCM.

• P1772 – Throttle Position Sensor Circuit Shorted to Transmission Control Module: Short circuit in the TPS signal wire going to the TCM.

• P1780 – Transmission Control Switch Circuit: Problem in the Transmission Control Switch circuit (e.g., Overdrive Off switch).

• P1780 – Overdrive Off Switch not Cycled during the Self Test: The Overdrive Off switch was not cycled during the self-test, as required for proper testing.

• P1781 – Transmission 4×4 Low Switch out of Range Fault: Redundant code, similar to P1729.

• P1783 – Transmission Fluid Temperature High Input: High temperature reading from the TFT sensor, indicating potential overheating of the transmission fluid.

• P1788 – 3-2T/CCS Circuit Open: Open circuit in the 3-2 Timing/Coast Clutch Solenoid (3-2T/CCS) circuit.

• P1789 – 3-2T/CCS Circuit Shorted: Short circuit in the 3-2T/CCS circuit.

• P1794 – Powertrain Control Module Battery Direct Power Circuit: Problem in the direct battery power supply circuit to the PCM, separate from the switched ignition power.

• P1797 – P/N Switch Open or Short Circuit: Park/Neutral (P/N) switch circuit is open or shorted. The P/N switch indicates if the transmission is in Park or Neutral, important for starting and other functions.

• P1900 – Turbine Speed Sensor Circuit Intermittent: Intermittent signal from the Turbine Speed Sensor (TSS) in the transmission. The TSS measures input shaft speed.

• P1901 – Torque Converter Clutch Circuit Intermittent: Intermittent fault in the Torque Converter Clutch circuit.

This comprehensive list of 2003 Protege Obd2 codes provides a valuable starting point for diagnosing check engine light issues. Remember to use an OBD2 scanner to retrieve the specific code from your vehicle and then consult this list for potential meanings. For accurate diagnosis and repair, always consult with a certified mechanic. Regular maintenance and prompt attention to warning lights can keep your 2003 Mazda Protege running smoothly for years to come.