Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1993SPORTVAN G30, VAN PASSENGER, 7.4 NREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 24 (ENGINE CONTROLS - TESTS W/CODES - 6.5L DIESEL)SELF-DIAGNOSTIC SYSTEMTROUBLE CODE IDENTIFICATION
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 N
Trouble Code Identification
1993 Chevrolet Sportvan G30, Van Passenger, 7.4 NSECTION Trouble Code Identification
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Rally Camper Special, 1994 GMC Rally, and 1994 GMC Forward Control. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Trouble codes retrieved from PCM may be either engine or transmission related. Only engine-related codes are covered in this article. For transmission-related codes, see the AUTO TRANS DIAGNOSIS - 4L60-E & 4L80-E article in this section. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION table to determine if code is engine or transmission related.
- The DEC system codes indicate failure of a specific sensor and/or circuit. Sensor/circuit diagnosis may indicate replacement of PCM. DTC 51 indicates PROM is either improperly installed or has failed.
- If PCM is replaced at any point during diagnostic testing and if condition is still not corrected after replacing PCM, the following may be the cause:
- An incorrect PCM or PROM application may cause a malfunction, which may or may not set a code.
- The PCM connector may be the problem. Connector terminals may have to be removed from connector to be checked properly.
- PROM failure. Although the PROM rarely fails, it could be the cause of the problem.
- Replacement PCM may be faulty.
- Intermittent problem. Make a careful physical inspection of affected sensor/circuit.
- A shorted solenoid, coil relay, or harness may be the cause of PCM failure. Use Short Circuit Tester (J-34636) to check for short circuits.
DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
| Code | Probable Cause | ||||
|---|---|---|---|---|---|
| 13 (1) | Engine Shutoff Solenoid Circuit Fault | ||||
| 14 (1) | ECT Sensor Circuit Low (High Temp. Indicated) | ||||
| 15 (1) | ECT Sensor Circuit High (Low Temp. Indicated) | ||||
| 16 (1) | Vehicle Speed Sensor Buffer Fault | ||||
| 17 (1) | High Resolution Circuit Fault | ||||
| 18 (1) | Pump Cam Reference Pulse Error | ||||
| 19 (1) | Crankshaft Position Reference Error | ||||
| 21 (1) | Accelerator Pedal Position No. 1 Circuit High | ||||
| 22 (1) | Accelerator Pedal Position No. 1 Circuit Low | ||||
| 23 (1) | Accelerator Pedal Position No. 1 Circuit Range Fault | ||||
| 24 (2) | Vehicle Speed Sensor Transmission Output Signal | ||||
| 25 (1) | Accelerator Pedal Position No. 2 Circuit High | ||||
| 26 (1) | Accelerator Pedal Position No. 2 Circuit Low | ||||
| 27 (1) | Accelerator Pedal Position No. 2 Circuit Range Fault | ||||
| 28 (2) | Trans. Range Pressure Switch | ||||
| 29 (1) | Glow Plug Relay Circuit Fault | ||||
| 31 (1) | EGR Control Pressure/BARO Sensor Circuit Low (High Vacuum) | ||||
| 32 (1) | EGR Circuit Error | ||||
| 33 (1) | EGR Control Pressure/BARO Sensor Circuit High (Low Vacuum) | ||||
| 34 (1) | Injection Timing Stepper Motor Circuit Fault | ||||
| 35 (1) | Injection Pulse Width Error (Response Time Short) | ||||
| 36 (1) | Injection Pulse Width Error (Response Time Long) | ||||
| 37/38 (2) | TCC Brake Switch On/Off | ||||
| 39 (2) | TCC Stuck Off | ||||
| 41 (1) | Brake Switch Circuit Fault | ||||
| 42 (1) | Fuel Temperature Circuit Low (High Temp. Indicated) | ||||
| 43 (1) | Fuel Temperature Circuit High (Low Temp. Indicated) | ||||
| 44 (1) | EGR Pulse Width Error | ||||
| 45 (1) | EGR Vent Error | ||||
| 46 (1) | MIL (SERVICE ENGINE SOON) Circuit Fault | ||||
| 47 (1) | IAT Sensor Circuit Low (High Temp. Indicated) | ||||
| 48 (1) | IAT Sensor Circuit High (Low Temp. Indicated) | ||||
| 49 (1) | SERVICE THROTTLE SOON Light Circuit Fault | ||||
| 51 (1) | PROM Error (Faulty Or Incorrect PROM) | ||||
| 52/53 (2) | System Voltage High | ||||
| 54 (1) | PCM Fuel Circuit Error | ||||
| 56 (1) | Injection Pump Calibration Resistor Error | ||||
| 57 (1) | PCM 5-Volt Shorted | ||||
| 58 (2) | Transmission Fluid Temperature High | ||||
| 59 (2) | Transmission Fluid Temperature Low | ||||
| 61 (1) | Turbo Boost Sensor Circuit High | ||||
| 62 (1) | Turbo Boost Sensor Circuit Low | ||||
| 63 (1) | Accelerator Pedal Position No. 3 Circuit High | ||||
| 64 (1) | Accelerator Pedal Position No. 3 Circuit Low | ||||
| 65 (1) | Accelerator Pedal Position No. 3 Circuit Range Fault | ||||
| 66 (2) | 3-2 Control Solenoid Circuit Fault | ||||
| 67 (2) | TCC Solenoid Circuit Check | ||||
| 68 (2) | Overdrive Ratio Error | ||||
| 69 (2) | Torque Converter Clutch Stuck On | ||||
| 71 (1) | Set/Coast Switch Fault | ||||
| 72 (2) | VSS Circuit Loss Transmission Output Signal | ||||
| 73 (2) | Pressure Control Solenoid (Current Error) | ||||
| 74 (2) | Trans. Input Speed Error | ||||
| 75 (2) | System Voltage Low | ||||
| 76 (1) | Resume/Accel Switch Fault | ||||
| 78 (1) | Wastegate Solenoid Fault | ||||
| 79 (2) | Transmission Fluid Temperature High | ||||
| 81 (2) | Transmission 2-3 Error | ||||
| 82 (2) | Transmission 1-2 Error | ||||
| 83 (2) | TCC Solenoid Circuit Fault | ||||
| 84 (1) | Accelerator Pedal Position Circuit Fault | ||||
| 85 (2) | Undefined Gear Ratio | ||||
| 86 (2) | Low Gear Ratio Error | ||||
| 87 (2) | High Gear Ratio Error | ||||
| 88 (1) | TDC Offset Error | ||||
| 91 (1) | Cylinder Balance Fault No. 1 Cylinder | ||||
| 92 (1) | Cylinder Balance Fault No. 2 Cylinder | ||||
| 93 (1) | Cylinder Balance Fault No. 3 Cylinder | ||||
| 94 (1) | Cylinder Balance Fault No. 4 Cylinder | ||||
| 95 (1) | Cylinder Balance Fault No. 5 Cylinder | ||||
| 96 (1) | Cylinder Balance Fault No. 6 Cylinder | ||||
| 97 (1) | Cylinder Balance Fault No. 7 Cylinder | ||||
| 98 (1) | Cylinder Balance Fault No. 8 Cylinder | ||||
| 99 (1) | Accelerator Pedal Position No. 2 (5-Volt Reference Fault) | ||||
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.