Crankshaft Position Sensor A Circuit Low
What does P0337 mean?
The P0337 code means the vehicle's onboard diagnostic system has detected: Crankshaft Position Sensor A Circuit Low. This is a critical severity code.
Common Symptoms
- Engine cranks but will not start
- Engine stalls suddenly
- Tachometer drops to zero
- Check Engine Light illuminated
- No spark or fuel injection
Probable Causes (Ranked by Likelihood)
- Short to ground in CKP sensor signal wiring Very High
- Faulty CKP sensor with internally shorted coil High
- Corroded or damaged CKP sensor connector High
- CKP sensor contaminated with oil or metal debris Moderate
- PCM input circuit failure Low
Step-by-Step Diagnostic Procedure
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Check CKP sensor signal voltage during cranking -- should produce AC voltage; consistently low or zero indicates a fault
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Test for shorts to ground in the signal wire with the sensor disconnected
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Inspect the sensor tip for metal debris buildup from the reluctor ring -- clean or replace
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Check the sensor connector for oil intrusion, corrosion, or damaged pins
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Measure sensor coil resistance -- compare to manufacturer specification
Frequently Asked Questions
Can I drive with code P0337?
No. A low CKP circuit means the PCM is not receiving a proper engine position signal. The engine may not start or may stall unpredictably.
Can metal debris on the sensor cause P0337?
Yes. The CKP sensor uses a magnet, and metal shavings from the reluctor ring or engine components can accumulate on the sensor tip, disrupting the signal and causing a low reading.
How often should the CKP sensor be replaced?
CKP sensors do not have a standard replacement interval. They typically last the life of the engine. Replace only when faulty, not as preventive maintenance.