P1376 is a manufacturer-specific OBD-II diagnostic trouble code. Its exact definition depends entirely on the vehicle application, ranging from ignition ground circuit faults to specific cylinder ignition timing issues.
The exact application must be verified before diagnosis. The code indicates the control module detected a fault, but testing is required to identify the root cause.
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Key Takeaways
- P1376 is a manufacturer-specific code, meaning its exact definition varies by automaker and vehicle application.
- On many GM and Saturn applications, it indicates an ignition control module ground circuit fault or low reference voltage.
- On some Ford and Jaguar applications, it indicates an early activation fault for the ignition coil on cylinder 6.
- Diagnosis requires verifying the exact factory definition and testing the relevant ignition ground circuits or coil timing components.
P1376 Code Description and Implications
P1376 is a manufacturer-specific powertrain code. Because the second digit is “1”, the definition is controlled by the automaker rather than the SAE standardized list.
Some GM, Cadillac, and Saturn applications: P1376 indicates an Ignition Control Module ground circuit malfunction or low reference voltage. The powertrain control module detects an issue with the electrical ground path for the ignition system.
Some Ford and Jaguar applications: P1376 indicates an Ignition Coil Cylinder 6 Early Activation Fault. The control module detects that the ignition coil for cylinder 6 is firing earlier than the expected timing parameters.
When the control module detects an unexpected signal, it sets these error codes.
Common Causes of the P1376 Code
Possible causes depend entirely on the specific vehicle application.
For GM and Saturn ignition ground circuit applications, a corroded or broken ignition ground wire, a failing ignition control module, damaged module wiring, or poor electrical connections can trigger the code.
For Ford and Jaguar ignition timing applications, a failing ignition coil on cylinder 6, damaged coil wiring, a poor electrical connection, or a failing crankshaft position sensor can trigger the early activation fault.
Symptoms Associated With P1376
The primary symptom is an illuminated Check Engine Light.
On GM and Saturn applications, drivers may experience engine misfires, rough idling, hesitation, or a no-start condition due to the ignition control module losing its ground path.
On Ford and Jaguar applications, symptoms include a severe misfire on cylinder 6, rough running, hesitation during acceleration, and decreased fuel efficiency.
Diagnosing the P1376 Trouble Code
Diagnosis must begin by confirming the exact factory definition for the specific make, model, and year.
For GM and Saturn applications, technicians inspect the ignition control module ground wiring for corrosion or opens, test the module reference voltage, and verify the ground connections are clean and tight.
For Ford and Jaguar applications, technicians inspect the cylinder 6 ignition coil wiring, test the coil primary and secondary resistance, and verify the crankshaft position sensor signals.
Repairing the P1376 Issue
Repairs follow the confirmed diagnosis for the specific application.
If an ignition ground wire is corroded or broken on a GM application, repairing the harness and cleaning the ground connection restores the circuit. Replacing a failing ignition control module may also be necessary.
If an ignition coil or spark plug fails testing on a Ford or Jaguar application, replacing the confirmed failed component resolves the misfire or circuit fault.
Cost Considerations for P1376 Repairs
Repair costs vary depending on the underlying fault and the vehicle application.
Repairing a damaged ground wire involves minimal parts and labor. Replacing an ignition control module or addressing internal coil timing faults requires more diagnostic time and parts.
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Prevention Strategies for Future Occurrences
Some electrical and mechanical failures cannot be reliably prevented.
Inspecting exposed ignition wiring and keeping module ground connections clean can help prevent moisture intrusion and corrosion that lead to ground circuit faults.
Performing regular spark plug replacements at the manufacturer-recommended intervals helps prevent misfires caused by worn electrodes on applicable vehicles.
Troubleshooting Tips and Best Practices
Never assume a manufacturer-specific code has a universal meaning. Always verify the exact factory service information for your specific vehicle.
Do not replace an ignition control module or ignition coil without first verifying the wiring, ground connections, and sensor signals.
If P1376 is accompanied by other random misfire codes, suspect a shared wiring harness issue, a failing crankshaft position sensor, or a systemic ground fault rather than multiple simultaneous component failures.
More OBD-II Codes
| P1370 | P1371 | P1372 | P1373 |
| P1374 | P1375 | P1377 | P1378 |
| P1380 | P1381 | P1382 | P1386 |
| P0300 | P0306 | P0335 | P1350 |
| P1344 | P1345 | P1346 | P1347 |
| P1348 | P1349 | P1358 | P1359 |
Frequently Asked Questions
Is P1376 a generic OBD-II code?
No. P1376 is a manufacturer-specific code, meaning its exact definition and diagnostic procedure depend entirely on the vehicle’s make, model, and application.
Can I drive my vehicle with a P1376 code?
It depends on the application. If it indicates a severe misfire or ignition module failure, driving the vehicle can cause catalytic converter or engine damage and should be avoided.
Will a P1376 code cause my engine to misfire?
Yes. On applications where P1376 indicates an ignition ground circuit or cylinder 6 coil fault, the lack of spark or incorrect timing will cause the engine to misfire.
Does P1376 always mean the ignition control module is broken?
No. The code often points to a corroded ground wire, damaged wiring, a poor electrical connection, or a failing crankshaft position sensor rather than a failed module.
How do I clear a manufacturer-specific P1376 code?
Clearing the code requires fixing the underlying ignition ground circuit or coil timing fault. Simply using a scan tool to erase the code will not repair the root cause.
What Should You Do About the P1376 Code?
Confirm the exact factory definition for your specific vehicle, then follow the applicable manufacturer diagnostic procedure for the relevant system and components.
Because P1376 is manufacturer-specific, testing the exact ignition ground circuits, control modules, or cylinder 6 ignition coils identified by the factory service information is required to find the root cause.
Once the fault is confirmed, perform the necessary repairs and verify the fix by clearing the codes and completing a test drive.
