Draft guidance: awaiting Claude spot-check, qualified-mechanic review and named-editor approval. Do not use a fault code alone to replace parts.

P0335: Crankshaft position sensor A circuit malfunction

The engine computer is not receiving the expected signal from crankshaft-position sensor circuit A.

What P0335 means

The engine computer is not receiving the expected signal from crankshaft-position sensor circuit A. The fault may lie in the sensor, wiring, connector, trigger wheel, timing system or—rarely—the control module; the code is not proof that the sensor alone is defective.

Can I still drive?

Driving is not recommended because the engine can stall without warning and may not restart. If the code appears while driving, reduce load, stop in a safe place and arrange recovery. A no-start, repeated stalling or absent engine-speed reading during cranking needs immediate diagnosis rather than repeated start attempts.

Symptoms

  • Extended cranking, intermittent no-start or complete no-start.
  • Sudden stalling.
  • Rough running, stumble, hesitation or misfire.
  • Reduced acceleration.
  • No RPM signal on suitable scan data while cranking.

Common causes

  • Failed crankshaft-position sensor.
  • Loose, corroded, open or shorted sensor circuit.
  • Poor sensor power supply or earth where applicable.
  • Damaged, dirty, loose or misaligned reluctor/tone wheel.
  • Slipped or failed timing belt or chain.
  • Rare control-module or software fault.

Safe first checks

  • Save all codes, especially camshaft or timing-correlation faults. Check for obvious battery-terminal looseness or low-voltage symptoms. With the ignition off and engine cool, inspect the accessible sensor plug and loom for oil contamination, heat damage, chafing or broken clips. A scan tool may show whether RPM is reported during cranking, but keep hands, leads and tools clear of belts and fans. Do not dismantle timing parts without the correct procedure.

Typical UK fix cost

Allow £90–£180 for diagnosis and approximately £170–£500 total for a typical sensor or wiring repair. Poor access can push this towards £600–£800. If testing identifies a timing belt, chain or trigger-wheel problem, a realistic broad range is £650–£2,000+.

Related models

This is a generic OBD-II code used across many makes and models. The exact test thresholds, component layout and repair route vary by engine and manufacturer, so check vehicle-specific technical information before ordering parts.

Related fault codes

Sources

A diagnostic trouble code identifies a system or circuit to investigate. It does not prove that a named part has failed. Preserve freeze-frame data and seek a vehicle-specific diagnosis before clearing the code.