The 1994 Chevy S10 Blazer, a popular SUV of its time, utilizes an On-Board Diagnostics system, specifically OBD1, to monitor engine and emission control systems. When your “Service Engine Soon” light illuminates, it indicates that the vehicle’s computer has detected a problem. Understanding how to retrieve and interpret these OBD1 codes is the first step towards diagnosing and repairing issues yourself or communicating effectively with a mechanic. This guide provides a comprehensive 1994 S10 Blazer OBD1 codes list and explains how to access these codes.
Reading OBD1 Trouble Codes on Your 1994 S10 Blazer
Retrieving OBD1 codes on your 1994 S10 Blazer is a straightforward process that doesn’t require any special tools, just a simple paper clip or a short piece of wire. Here’s how to do it:
- Locate the DLC Connector: The Diagnostic Link Connector (DLC), also known as the Assembly Line Diagnostic Link (ALDL) connector, is usually found under the driver’s side dashboard.
Alt text: Location of A and B terminals on the OBD1 DLC connector for reading diagnostic codes on a 1994 Chevy S10 Blazer.
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Prepare to Jumper Terminals: With the ignition switch turned off, use your paper clip or wire to bridge the “A” and “B” terminals on the DLC connector. These terminals are typically located at the top right of the connector, as illustrated above.
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Turn Ignition On: Turn the ignition key to the “ON” position, but do not start the engine.
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Observe the “Service Engine Soon” Light: Watch the “Service Engine Soon” light on your dashboard. It will begin to flash a sequence of codes.
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Interpret the Codes: OBD1 codes are communicated through flashes of the “Service Engine Soon” light. A code is represented by a series of flashes, a pause, and then more flashes.
- Code 12 is the system’s “start of test” indicator and is normal. It’s represented by one flash, pause, two flashes.
- Each code, including code 12, will be displayed three times before moving to the next code in numerical order.
- The entire sequence of codes will repeat continuously until you turn the ignition off or remove the jumper.
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Record the Codes: Carefully count and record each code as it is flashed.
Important Notes on OBD1 Codes:
- Code 12 is Normal: Code 12 simply indicates that the diagnostic system is functioning and is not a fault code.
- Codes are Starting Points: Remember that an OBD1 code points to a potential issue but doesn’t definitively identify the faulty component. A code indicates that a sensor or system is reporting data outside of its expected range. Further diagnostic steps are necessary to pinpoint the root cause of the problem.
- Not All Codes Apply: This list is for gasoline engines and may not include all possible codes for every system in your 1994 S10 Blazer.
1994 S10 Blazer OBD1 Codes List (Gasoline Engines)
Here is a list of common OBD1 trouble codes for gasoline engine 1994 Chevy S10 Blazers:
- 13 – O2 Sensor Circuit Open
- 14 – ECT/CTS Sensor Circuit Low (High Temperature)
- 15 – ECT/CTS Sensor Circuit High (Low Temperature)
- 16 – VSS Buffer Fault
- 21 – TPS Circuit High (Signal Voltage High)
- 22 – TPS Circuit Low (Signal Voltage Low)
- 24 – VSS Circuit Low
- 28 – Transmission Range Pressure Switch Assembly
- 32 – EGR Valve Error
- 33 – MAP Sensor Circuit High (Low Vacuum)
- 34 – MAP Sensor Circuit Low (High Vacuum)
- 35 – IAC Error
- 36 – Idle Speed Control Actuator Error (if equipped)
- 42 – IC Error
- 43 – KS Error
- 44 – Lean Exhaust
- 45 – Rich Exhaust
- 51 – PROM Error
- 53 – System Voltage High (Supply to ECM/PCM)
- 54 – Fuel Pump Relay Circuit Low Voltage
- 55 – ECM/PCM Error
Clearing OBD1 Codes
After addressing the issue indicated by the OBD1 code, you’ll want to clear the codes and turn off the “Service Engine Soon” light. Here are a couple of ways to clear OBD1 codes on your 1994 S10 Blazer:
- Battery Disconnection: Disconnecting the negative battery cable for approximately 20 seconds will typically clear the stored OBD1 codes.
- Automatic Clearing: If the fault condition that triggered the code does not reappear for 50 engine starts, the codes will automatically clear themselves.
Conclusion
Understanding and utilizing the OBD1 diagnostic system in your 1994 Chevy S10 Blazer can save you time and money in diagnosing potential issues. By following these steps to read and interpret the trouble codes, you can gain valuable insights into your vehicle’s health and take appropriate action. Remember that these codes are a starting point, and further investigation may be needed to accurately pinpoint and resolve the underlying problem. If you are unsure about diagnosing or repairing your vehicle, always consult a qualified automotive technician.
