P0371: Timing Reference High Resolution Signal A Too Many Pulses
The PCM has detected an excessive number of pulses from the high-resolution crankshaft position sensor (signal A) compared to the expected pattern. This indicates a fault in the sensor circuit, a damaged reluctor wheel, or electrical interference, causing incorrect timing reference for fuel injection and ignition.
1. Most Common Causes
- Faulty or contaminated high-resolution crankshaft position (CKP) sensor (e.g., metal shavings on sensor tip)
- Damaged crankshaft reluctor ring (missing or extra teeth)
- Short circuit in CKP sensor wiring or connectors (short to voltage, ground, or between signal wires)
- Internal PCM failure in the frequency reading circuit
- Mechanical misalignment of the CKP sensor or reluctor wheel
2. Symptoms You Will Notice
- Check Engine Light on
- Engine misfire or rough idle
- Hard starting or no start
- Reduced engine power and poor fuel economy
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect the crankshaft position sensor and wiring for damage or corrosion.
Step 3: Test sensor resistance and AC voltage output while cranking; compare to specs.
Step 4: Inspect the reluctor wheel for damaged or missing teeth via borescope if necessary.
Step 5: Check for electrical interference from nearby components (e.g., spark plug wires).
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with P0371 can cause engine stalling, poor performance, and potential damage to the catalytic converter. It is best to have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a sensor replacement, plus diagnostic fees. Labor may add $50-$100 depending on the vehicle.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.