OBD Code P0335: Crankshaft Position Sensor Circuit — Random Stalling Risk

What does code P0335 mean?

Code P0335 (Crankshaft Position Sensor A Circuit Malfunction) means the ECU is receiving no signal or an erratic signal from the crankshaft position sensor (CKP). Without this signal, the ECU cannot time injection or ignition — the engine can't run.

Risk: sudden stalling at any speed, including motorway speeds.

Symptoms

• Check engine light
• Random stalling — the engine cuts out without warning
• Difficult or impossible starts
• Irregular misfires
• Engine cranks but won't fire

⚠️ Do not use the motorway with an active P0335. Sudden engine cutout at speed is a serious road safety hazard.

Causes

1. Failed CKP sensor (60%)

The inductive or Hall effect sensor wears with age and heat cycling. Replacement is simple and cheap.

👉 Crankshaft position sensor on Amazon UK — £12-40, use branded (Bosch, Delphi)

DIY replacement (30-45 min):

1. Locate sensor at the bottom of the engine block near the flywheel/tone ring
2. Unplug connector
3. Remove 1-2 M6 bolts
4. Install new sensor (clean mating surface)
5. Torque to 8-12 Nm, clear code

2. Damaged tone ring (reluctor ring)

A broken or missing tooth on the tone ring gives an abnormal signal. Visible on inspection.

3. Wiring/connector fault

The cable runs near hot exhaust components and can burn through. Inspect carefully.

Repair cost

P0335 + P0340 together?

Two sensor codes together can indicate a timing chain/belt that has jumped a tooth. Check for P0016 as well — if present, don't drive.