GM ECM/PCM Codes
| Code |
Model |
Engine |
Code Description |
| 12 |
All |
|
No Distributor Reference at ECM |
| 13 |
All |
|
Open in Oxygen Sensor Circuit |
| 14 |
All |
|
Coolant Temp Circuit Grounded |
| 15 |
All |
|
Coolant Temp Circuit Open |
| 16 |
PFI |
3.8L-3800 |
System Voltage Overcharge Occurred |
| 21 |
All |
|
TPS Signal Voltage High |
| 22 |
All |
|
TPS Signal Voltage Low |
| 23 |
Carb |
|
M/C Solenoid Circuit Open/Shorted |
| 23 |
FI |
|
MAT Showing Excessive Low Temperature |
| 24 |
All |
|
Park/Neutral or VSS Circuit |
| 25 |
TBI |
2.0L & 2.5L |
MAT Showing Excessive High Temperature |
| 26 |
MFI |
|
Injector Quad Driver Failure |
| 27 |
PFI |
3.8L - 3800 |
2ND Gear Switch Error |
| 28 |
PFI |
3.8L - 3800 |
3RD Gear Switch Error |
| 29 |
PFI |
3.8L - 3800 |
4TH Gear Switch Error |
| 31 |
PFI Turbo |
3.8L |
Shorted or Open Wastegate Solenoid |
| 31 |
Carb |
|
Purge Solenoid Circuit Open/Shorted |
| 31 |
PFI |
3.8L - 3800 |
Park/Neutral Incorrectly Sensed |
| 32 |
Carb |
|
Barometric Pressure Sensor Indicating Low Value |
| 32 |
FI |
|
EGR Vacuum Sensed at Wrong Time |
| 33 |
TBI |
2.0L & 2.5L |
MAP Sensor Circuit Signal High |
| 33 |
PFI |
|
MAF Signal Showing Excessive High Airflow |
| 34 |
TBI-Carb |
|
MAP Vacuum Sensor Out of Range |
| 34 |
TBI-Carb |
|
MAP Sensor Circuit Signal Low |
| 34 |
PFI |
|
MAF Signal showing Excessive Low Airflow |
| 35 |
TBI-Carb |
|
ISC Nose Switch Showing Continuous Closed |
| 35 |
FI |
|
Idle Speed Control (IAC) Error |
| 36 |
PFI |
5.0L - 5.7L |
MAF Burn-off Not Noted to Occur |
| 36 |
PFI |
Quad 4 - 2300 |
Closed Throttle Airflow High |
| 38 |
PFI |
3.8L - 3800, 3.3L |
Brake Switch Error |
| 39 |
PFI |
3.8L - 3800, 3.3L |
TCC Circuit Error |
| 41 |
PFI |
C3I |
Missing or Erratic CAM Sensor Signal |
| 41 |
PFI |
2.8L, 5.0L - 5.7L |
Cylinder Select Value Mismatch |
| 41 |
All |
|
No Distributor Reference at ECM with Engine Running |
| 42 |
All |
|
EST Signal or EST By-Pass Toggled High/Low Incorrectly |
| 42 |
PFI |
C3I |
C3I EST Signal Not Toggling Correctly |
| 43 |
All |
|
ESC Signaling for Prolonged Retard Too Long |
| 44 |
All |
|
O2 Signaling Lean Condition Too Long |
| 45 |
All |
|
O2 Signaling Rich Condition Too Long |
| 46 |
PFI |
5.7L Y-Body |
Vehicle Anti-Theft System Inoperative |
| 46 |
PFI |
3.3L |
Power Steering Switch Showing ON Too Long |
| 48 |
PFI |
3.8L - 3800 |
Ignition Misfire Noted |
| 51 |
All |
|
PROM Failure to Handshake with ECM |
| 51 |
PFI |
2.8L, 5.0L - 5.7L |
MEM-CAL Failure |
| 52 |
TBI |
2.0L & 2.5L |
CALPAC Missing or Defective |
| 52 |
PFI |
5.7L Y-Body |
Engine Oil Temperature LOW Too Long |
| 53 |
FI |
|
EGR Control Sensed at Wrong Time |
| 53 |
PFI |
2.8L, 5.0L - 5.7L |
System Voltage Overcharge Occurred |
| 53 |
PFI |
5.0L Y-Body |
ECM Not Seeing VATS Decoder Signal |
| 54 |
|
|
M/C Circuit Shorted to 12 Volt Source or Faulty ECM |
| 54 |
TBI |
2.0L & 2.5L |
Low Fuel Pump Voltage |
| 55 |
All |
|
ECM Failure |
| 61 |
FI |
2.8L & 3.1L |
Lazy Oxygen Sensor |
| 62 |
PFI |
2.3 Quad |
4 Gear Switch Error |
| 62 |
PFI |
5.7 Y-Body |
Engine Oil Noted to Exceed Temerature Tolerance |
| 63 |
FI |
2.8L |
High MAP Sensor Value |
| 63 |
PFI |
3.8L - 3800 |
EGR Control Circuit Open/Shorted |
| 64 |
FI |
2.8L |
Low MAP Sensor Value |
| 65 |
PFI |
3.8L - 3800 |
EGR Control Circuit Open/Shorted |
| 65 |
PFI |
2.3 Quad 4 |
Low Injector Current Flow |
| 66 |
PFI |
2.3L Quad 4 & 3.3L |
A/C Pressure Sensor Voltage Out of Range |