Diagnostic trouble code P1374 is a manufacturer-specific powertrain fault code. Because it is manufacturer-specific, its exact definition depends entirely on the vehicle make, model, and application.
Exact vehicle application must be verified before diagnosis. The code identifies a detected condition in a specific subsystem, but further testing is required to identify the root cause.
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Key Takeaways
- P1374 is a manufacturer-specific code, meaning its definition varies between automakers like General Motors and Ford.
- On GM applications, it indicates a 3X reference circuit fault, relating to the signal between the ignition control module and the PCM.
- On some other applications, it may point to a crankshaft position sensor correlation or ignition coil early activation fault.
- Diagnosis requires verifying the exact factory definition and testing the relevant crankshaft sensor or ignition control circuits.
P1374 Code Description and Implications
Because P1374 is manufacturer-specific, there is no single universal definition. This error code identifies a detected condition, but the exact monitored system depends on the vehicle make and model.
Some General Motors applications: P1374 indicates a “3X Reference Circuit” fault. The ignition control module generates a 3X signal used by the PCM for fuel injection and spark timing.
If the PCM detects an incorrect number of pulses on this circuit, it triggers the code.
Certain Ford and other applications: P1374 may indicate a crankshaft position sensor high-to-low resolution frequency correlation issue or an early activation fault in the ignition coil circuit.
Common Causes of the P1374 Code
The underlying cause depends entirely on the verified factory definition for the specific vehicle application.
For GM applications, possible causes include a failing ignition control module, a faulty crankshaft position sensor, or damaged wiring in the 3X reference circuit.
For other applications, causes may involve a failing crankshaft position sensor, damaged sensor wiring, or poor electrical connections at the sensor harness.
Symptoms Associated With P1374
Symptoms vary widely depending on the underlying system fault and the vehicle manufacturer.
On GM applications with a 3X reference circuit fault, symptoms can include engine stalling, rough idling, reduced power, and an illuminated Check Engine Light.
On other applications with a crankshaft position correlation fault, symptoms may include hesitation during acceleration, a no-start condition, and severe engine misfires.
Diagnosing the P1374 Trouble Code
Diagnosis must begin by confirming the exact factory definition for the specific make, model, and year.
For GM applications, technicians inspect the 3X reference circuit wiring for opens or shorts, test the ignition control module output, and verify the crankshaft position sensor signals.
For other applications, technicians test the crankshaft position sensor circuits, inspect the wiring harness, and compare the high and low resolution signals using an oscilloscope.
Repairing the P1374 Issue
Repairs must follow confirmed diagnosis based on the specific vehicle application.
If a 3X reference circuit fault is confirmed on a GM application, the damaged wiring must be repaired, or the ignition control module or crankshaft position sensor replaced.
If a crankshaft position correlation fault is confirmed on other applications, the sensor or damaged wiring must be replaced or repaired.
Cost Considerations for P1374 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing a crankshaft position sensor or ignition control module may require minimal labor depending on accessibility.
Conversely, diagnosing intermittent wiring faults or replacing sensors buried behind the harmonic balancer requires significant labor.
Prevention Strategies for Future Occurrences
Some electrical and mechanical failures cannot be reliably prevented.
Inspecting exposed wiring harnesses for chafing or heat damage can help prevent intermittent circuit faults in the crankshaft sensor or ignition control systems.
Keeping connector seals intact may reduce moisture intrusion that leads to corrosion and signal loss.
Troubleshooting Tips and Best Practices
Never assume P1374 is a universal crankshaft sensor code. Always verify the exact definition for the specific vehicle before purchasing parts.
Do not ignore related codes. A 3X reference fault may appear alongside camshaft position sensor codes or specific cylinder misfire codes.
Check for technical service bulletins applicable to your exact vehicle application, as manufacturers frequently release updated sensors or revised wiring harnesses for recurring faults.
More OBD-II Codes
| P1367 | P1375 | P0335 | P0171 |
| P1368 | P1376 | P0340 | P0174 |
| P1370 | P1377 | P0300 | P1108 |
| P1371 | P1378 | P0301 | P1109 |
| P1372 | P1380 | P1344 | P1345 |
| P1373 | P1381 | P1346 | P1347 |
Frequently Asked Questions
Is P1374 a generic or manufacturer-specific code?
No. P1374 is a manufacturer-specific code. Its exact definition varies significantly between automakers, so the factory service information for the specific vehicle must be consulted.
Can I drive my car with a P1374 code?
It depends on the application. If P1374 indicates a 3X reference circuit fault, the engine may stall or run poorly. If it is a crankshaft correlation fault, performance may be reduced.
Will disconnecting the battery clear the P1374 code?
Disconnecting the battery may temporarily clear the code, but it does not repair the underlying electrical or mechanical fault. The code will return once the monitor runs again.
Can a bad crankshaft position sensor cause a P1374 code?
On GM applications monitoring the 3X reference circuit, a failing crankshaft position sensor or ignition control module can prevent the correct pulse signal, triggering the fault code.
Does P1374 always mean the ignition control module is bad?
No. While a failing module is a cause on specific GM applications, the code can also indicate damaged wiring, a failing crankshaft position sensor, or poor electrical connections.
What Should You Do About the P1374 Code?
Confirm the exact factory definition and diagnostic procedure for your specific vehicle application. Because P1374 is manufacturer-specific, identifying whether it relates to a 3X reference circuit or a crankshaft position correlation fault is mandatory.
Follow the applicable manufacturer diagnostic steps to test the relevant system and components. Once the root cause is confirmed, complete the necessary repairs and verify that the system operates correctly and the code does not return.
