P0335
Crankshaft Position Sensor "A" Circuit Malfunction
The crankshaft position (CKP) sensor signal is missing or implausible. The CKP is essential — without it the ECU cannot synchronise injection or ignition, and the engine will not start or will stall.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
What we see in the workshop
ON FORD ECOBOOST
Crankshaft position sensor faults present as a no-start or a stall that clears on cooling. We check the sensor and its wiring under heat, because it often only fails when hot.
Common causes
Ordered by how often each turns out to be the cause.
- Sensor failed (heat damage common)Common
- Reluctor ring damaged or contaminated with metal debrisLess likely
- Wiring or connector faultPossible
Parts involved
- Crankshaft Position Sensor
- Reluctor Ring
- Crankshaft Position Sensor Wiring
P0335 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.