P0335 P0xxx · Powertrain (P) High severity
Crankshaft Position Sensor A Circuit Malfunction
No usable crank signal. Without it the ECU cannot time injection or ignition, so the engine will usually crank without starting.
Severity guidance: High — stop driving and diagnose now; risk of further damage
Symptoms you will notice
- Cranks but will not start
- Stalling while driving
- Tachometer dead while cranking
- No spark or injector pulse
Common causes
Ordered from most to least likely — start at the top.
- 1 Failed crankshaft position sensor
- 2 Damaged or heat-brittle wiring
- 3 Metal debris or a cracked reluctor wheel
- 4 Corroded connector
How to diagnose it
Cheapest and least invasive first — most of these codes are not a parts problem.
- ✓ Watch engine RPM in live data while cranking — no RPM reading confirms the signal is missing.
- ✓ Check the sensor connector and wiring for heat damage near the exhaust.
- ✓ Measure sensor resistance and AC voltage output while cranking.
- ✓ Scope the waveform — a clean square or sine with no dropouts is required.
Repair options
- Replace the crankshaft position sensor
- Repair the wiring
- Replace a damaged reluctor
P0335 — frequently asked questions
Can it be intermittent? +
Yes — heat-soak failures are classic: the car stalls when hot and restarts after cooling.
Why does the tachometer matter? +
If the tacho does not move while cranking, the ECU is not seeing engine speed — a fast way to confirm the fault.
Confirm the diagnosis before you buy parts
Send us the code, freeze-frame data and the vehicle — our engineers will tell you what to test first.