P0335 – Meaning, Symptoms, Causes & How to Fix It

P0335 – Crankshaft Position Sensor A Circuit indicates that the engine control unit is not receiving a valid signal from the Crankshaft Position Sensor (CKP). This sensor monitors crankshaft rotation to control ignition timing, fuel injection, and engine synchronization. When the CKP signal is missing, irregular, or electrically faulty, the engine may stall, fail to start, or run poorly. This guide explains what P0335 means, its symptoms, causes, diagnostic steps, and the most effective repair solutions.

What Does P0335 Mean?

P0335 is a generic OBD-II powertrain code that means the ECU cannot detect a proper signal from Crankshaft Position Sensor “A.” The CKP sensor provides the reference point the ECU uses to determine engine speed and crankshaft position. If the circuit is open, shorted, misaligned, or producing no signal, the ECU cannot manage ignition or fuel delivery correctly.

This code can cause serious drivability issues because the crankshaft sensor is essential for engine operation.

Quick Reference

OBD-II Family: P-Code (Powertrain)
Scope: Generic
System: Engine Speed / Crankshaft Position
Difficulty Level: Moderate–Advanced
Estimated Repair Cost: €90–€350+
Last Updated: 10 December 2025

Real-World Example / Field Notes

A vehicle arrived with intermittent stalling and difficulty starting. Live data showed sudden drops in RPM readings, indicating signal loss from the CKP sensor. The wiring harness near the crank pulley had rubbed through on a metal bracket, intermittently shorting the signal wire. Repairing the harness and securing it fixed the issue.

Another case involved a no-start condition after driving through deep water. Water entered the CKP sensor connector, causing complete signal loss. Drying and cleaning the connector restored normal operation.

Symptoms of P0335 – Crankshaft Position Sensor A Circuit

No-start condition: Engine cranks but does not fire.
Stalling: Engine may shut off unexpectedly while driving.
Rough running: Poor idle or misfires from incorrect timing data.
Loss of power: ECU cannot accurately control timing and fuel.
Tachometer drops: RPM signal may cut out suddenly.
Check engine light: Stores P0335 when signal is absent or faulty.

Common Causes of P0335

Most Common Causes

Failed crankshaft position sensor
Damaged wiring near crank pulley or exhaust
Corroded or loose CKP connector
Metal debris stuck to magnetic sensor tip
Incorrect sensor air gap

Less Common Causes

Failed reluctor ring (cracked, loose, or missing teeth)
ECU internal failure
Aftermarket flywheel or engine rebuild misalignment
Moisture intrusion from water crossings
Weak engine ground causing signal instability

Diagnosis: Step-By-Step Guide

Diagnosing P0335 requires testing the CKP sensor signal, circuit integrity, and mechanical condition of the reluctor ring.

Tools You’ll Need

OBD-II scanner, multimeter, oscilloscope (recommended), feeler gauge, wiring diagrams, and basic tools.

Check for no-start or stalling: Confirm if CKP failure is intermittent or complete.
Inspect wiring and connector: Look for heat damage, oil contamination, or corrosion.
Test CKP sensor resistance: Compare with factory specs.
Check for signal on oscilloscope: Look for a clean, consistent waveform.
Inspect reluctor ring: Check for cracks, missing teeth, or misalignment.
Verify air gap: Use a feeler gauge to confirm correct sensor-to-ring distance.
Check grounds: Poor grounding can disrupt low-voltage signals.
Check for metal shavings: Clean off the sensor tip if contaminated.
Compare RPM readings: If RPM shows “0” while cranking, CKP signal is missing.
Check ECU power and reference voltage: Confirm proper supply to the sensor.

Pro Tip: Many intermittent CKP problems come from wiring rubbing near the harmonic balancer. The harness is subject to vibration and heat — inspect closely before replacing the sensor.

Possible Fixes & Repair Costs

Replace crankshaft position sensor: €70–€150
Repair wiring or replace connector: €50–€140
Clean magnetic sensor tip: €0–€30
Replace damaged reluctor ring: €150–€400+
Correct air gap / reseat sensor: €0–€50
ECU repair or reflash (rare): €80–€300

Can I Still Drive With P0335?

If the engine still runs, avoid driving. P0335 can cause sudden stalling with no warning, which is dangerous in traffic. If the engine will not start, the vehicle must be repaired before operation. This fault is considered high priority due to the risk of losing crankshaft synchronization.

Last updated: March 1, 2026

Key Takeaways

P0335 indicates the ECU is not receiving a valid signal from the crankshaft sensor.
It can cause no-start conditions, stalling, and severe drivability issues.
Most faults are caused by sensor failure, wiring damage, or reluctor ring issues.
Do not drive the vehicle until the problem is diagnosed and repaired.

FAQ

Does P0335 mean the crankshaft sensor is bad?

Often yes, but wiring and reluctor ring problems are also common and should be checked first.

Can a weak battery cause P0335?

Yes. Low voltage during cranking can cause the ECU to lose the CKP signal temporarily.

Will the engine crank with a bad CKP sensor?

Yes, the engine will crank but usually will not start because the ECU cannot determine crankshaft position.

Can P0335 cause misfires?

Yes. Incorrect or missing CKP data leads to incorrect spark timing and misfires.

Will replacing the sensor fix the issue?

Only if the sensor is the cause. Always inspect wiring and the reluctor ring before replacing parts.

P0335 – Crankshaft Position Sensor “A” Circuit