P0335Powertrain
Powertrain · SAE
Crankshaft Position Sensor A Circuit — Fault
Meaning
The ECU is not receiving a valid signal from the crankshaft position sensor. Without this reference the controller cannot determine engine speed and position.
Common causes
- Failed or degraded crankshaft position sensor
- Open, shorted or corroded wiring/connector
- Damaged or contaminated reluctor (tone) ring, often with metal debris
- Incorrect air gap between sensor and reluctor ring
- Electrical interference or a faulty reference ground
- In some cases a timing issue or a jumped chain/belt
Symptoms
- No-start or hard-start condition
- Sudden stalling while driving
- Rough running with ignition cut-outs
- Check-engine light on
- Unstable or missing idle reading on the tachometer
Severity
High: the engine may fail to start or stall while driving, which is a safety risk.
What to do
- Read freeze-frame data and confirm whether an RPM signal is present during cranking
- Check the connector, wiring and ground with a multimeter/oscilloscope
- Inspect the reluctor ring and air gap, removing any metal filings
- Replace the sensor if the signal stays absent or erratic with wiring intact