Engine

P0335 — Crankshaft Position Sensor "A" Circuit Malfunction

Severity: high Do not drive

What P0335 means

The engine computer tracks crankshaft speed and position from pulses produced as the sensor reads a toothed tone ring (reluctor) on the crank. It uses this to time spark and fuel injection. P0335 sets when the signal from sensor "A" is missing, erratic or outside what the ECM expects.

Symptoms

  • Check Engine light on
  • Hard starting or no-start
  • Rough idle or misfires
  • Stalling while driving or at idle
  • Loss of power and sluggish acceleration
  • Intermittent cut-outs that may go away when the engine cools

Possible causes

  1. Failed crankshaft position sensor
  2. Damaged, corroded or loose wiring or connector
  3. Sensor contaminated with metal debris or oil
  4. Damaged or misaligned tone (reluctor) ring
  5. Incorrect sensor air gap or loose mounting
  6. Timing belt or chain problem upsetting crank synchronization
  7. Faulty ECM (rare)

How to diagnose

  1. Scan all codes and freeze-frame data, noting any camshaft sensor or misfire codes
  2. Crank the engine and see whether the scan tool shows an RPM reading
  3. Inspect the sensor, connector and harness for chafing, oil, corrosion or heat damage
  4. Check sensor mounting and air gap, then remove it and look for debris or damage
  5. Test power, ground and signal wires against the wiring diagram for that engine
  6. Measure the resistance of an inductive sensor or view the waveform on a scope while cranking
  7. Inspect the tone ring teeth and verify timing marks if needed
  8. If all is good, test the ECM and its power supplies

Common fixes

  • Replace the crankshaft position sensor
  • Repair the wiring or connector and clean the terminals
  • Replace or re-seat the tone ring
  • Correct engine timing, replacing the belt or chain and related parts
  • Reflash or replace the ECM once confirmed faulty

P0335 on different brands

Ford · manuals
Ford lists P0335:01 for its 2024–2025 gasoline engines; it identifies the specific monitor condition detected on the crankshaft sensor "A" circuit and does not by itself confirm a failed sensor.

Questions and answers

Can I drive with a P0335 code?

It is best not to. The engine can stall without warning, taking power steering and brake assist with it. Only drive carefully to a shop if the car starts.

Why does P0335 cause a no-start?

Without a crank signal the ECM does not know crankshaft position or speed, so it may not fire the spark or injectors. The starter usually still turns the engine over.

Do I always need a new crankshaft sensor?

No. Wiring, connector problems and debris on the sensor are common causes. Check the connections, air gap and tone ring before buying a sensor.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.