P0372 - Timing Reference High Resolution Signal A Too Few Pulses
The PCM has detected that the high resolution crankshaft position sensor (also known as the CKP sensor) is sending fewer pulses than expected. This signal is critical for engine timing and fuel injection synchronization. A low pulse count indicates a weak or intermittent signal, often due to sensor degradation, wiring issues, or a damaged reluctor wheel.
1. Most Common Causes
- Faulty or worn crankshaft position (CKP) sensor
- Damaged, dirty, or missing teeth on the reluctor ring or crankshaft pulley
- Sensor circuit wiring shorted to ground, shorted to voltage, or open
- Corroded, loose, or damaged sensor connector pins
- Excessive resistance in the signal circuit due to poor splices or deteriorated wires
- Intermittent ECM/PCM failure (less common)
2. Symptoms You Will Notice
- Engine cranks but does not start
- Rough idle or stalling
- Check Engine Light illuminated
- Poor acceleration or hesitation
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for related codes (e.g., P0335, P0336).
Step 2: Inspect the crankshaft position sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure sensor resistance and compare to manufacturer specifications; replace if out of range.
Step 4: Check reluctor wheel for damage, missing teeth, or excessive runout; repair or replace as needed.
Step 5: Verify sensor air gap using a feeler gauge; adjust if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The engine may stall unexpectedly or fail to start, leading to a breakdown or accident.
How much does it cost to fix?▼
Typically $50-$150 for a sensor replacement, but costs can be higher if wiring repairs or reluctor wheel replacement is needed.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.