P0337: Crankshaft Position Sensor "A" Circuit Low
P0337 means Crankshaft Position Sensor "A" Circuit Low. The crankshaft position (CKP) sensor tells the engine computer the crankshaft's position and speed. It is essential for spark and injection timing. The signal voltage is lower than the minimum the module expects. Typical causes are a short to ground, an open in the reference or signal wire, or a failed sensor.
Can I keep driving? Limit driving and diagnose promptly. Continued driving can cause damage, stalling or limp mode.
Common symptoms
- Engine cranks but does not start
- Intermittent stalling, often when hot
- Misfires or jerking
- Tachometer drops or behaves erratically
Possible causes
- Failed crankshaft position sensor
- Damaged tone ring (reluctor) or slipping harmonic balancer
- Wiring damage near the exhaust or moving parts
- Metal debris on a magnetic sensor
- Wrong sensor air gap after a repair
How to diagnose P0337
- Check whether the tachometer moves while cranking: no movement suggests no crank signal.
- Inspect connector and wiring.
- Check the sensor signal with a scope or meter while cranking.
- Inspect the tone ring through the sensor opening.
What the code means, digit by digit
Generic codes have the same definition on every OBD-II vehicle (petrol cars from model year 1996 in the US, 2001 in the EU; diesels later). Manufacturers can add their own enhanced codes; those are not listed here.
Related codes
General guidance only. Fault codes describe what the engine computer saw, not which part failed: confirm with testing before replacing parts, and follow the vehicle's service information.