P0335 — Crankshaft Position Sensor « A » Circuit

Introduction:
The P0335 trouble code indicates a problem with the crankshaft position sensor circuit. This sensor monitors the position and rotational speed of the crankshaft, a critical component for engine timing and fuel injection. When the ECU detects an irregularity or fault in this circuit, it triggers the P0335 code. Note that label variations may occur between different OEMs or vehicle manufacturers.

Fast Facts:

  • System affected: Engine Management / Crankshaft Position Sensor Circuit
  • Severity: Moderate
  • Main symptoms: Engine stalling, no-start condition, rough idle
  • Driveability: Limited / Yes—vehicle may run poorly or not at all

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Manufacturer variations for trouble code P0335

The P0335 code is a standardized OBD-II generic code, but manufacturers may label or reference this fault differently in their proprietary systems and diagnostic menus. Some common label variations include:

  • Ford: P0335 — Crankshaft Position Sensor Circuit Malfunction
  • Volkswagen/Audi: Usually labeled as « Engine Control Module » fault related to the Crankshaft Sensor
  • BMW: Often appears as a specific DTC related to the Crankshaft Position Sensor
  • Honda: May be identified as « Crankshaft Sensor Circuit Error »
  • General Motors: P0335 — Crankshaft Position Sensor « A » Circuit

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What does trouble code P0335 mean?

The P0335 code is set when the vehicle’s Engine Control Unit (ECU) detects a problem in the circuitry of the crankshaft position sensor. This sensor’s primary role is to relay the position and rotational speed of the crankshaft to the ECU, which uses this data to control spark timing and fuel injection.

A code P0335 is typically triggered by circumstances such as inconsistent signals, open circuits, short circuits, or a faulty sensor. This alert often appears when the ECU detects that the sensor’s signal is outside the expected parameters or absent altogether.

Typical situations include:
– Sudden engine stalling
– Failure to start
– Rough idling or hesitation during acceleration
– Erratic engine behaviour at various speeds

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Severity and risks of trouble code P0335

The P0335 fault can present various levels of risk depending on the severity of the sensor failure and the vehicle’s condition. If the sensor fails completely, the ECU cannot accurately determine the crankshaft’s position, leading to potential issues such as misfiring, stalling, or no-start conditions.

**Risks include:**
– Increased likelihood of engine stalls, especially at idle or low speeds
– Potential for damage to other engine management components due to incorrect timing
– Reduced fuel efficiency and possible increased emissions

**Can the vehicle be driven?**
Limited — The vehicle may be driven short distances if the failure is minor or intermittent, but it is generally not recommended to operate the vehicle extensively with this fault present. A complete sensor failure usually necessitates repairs before trustworthy operation.

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Symptoms of trouble code P0335

Common symptoms associated with a P0335 fault include:
– **Engine stalling or misfiring** unexpectedly, especially at idle
– **No-start condition** or difficulty starting the engine
– **Erratic engine behaviour**, including rough idling or hesitation
– **Check Engine Light (CEL)** illuminated on the dashboard
– **Reduced engine performance** or acceleration issues

Not all symptoms are conclusive, so proper testing and diagnostics are required to confirm the fault.

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Most likely causes of trouble code P0335

The P0335 code can result from various issues, but some causes are more frequent than others. This list reflects the most common problems that lead to this code being set:

  1. Defective Crankshaft Position Sensor: The sensor itself fails due to age, heat, or physical damage.
  2. Damaged or Corroded Wiring or Connectors: Poor connections, frayed wiring, or corrosion can interrupt the sensor signal.

    3. 3. Faulty Sensor Circuit or ECU Issue: Problems within the wiring harness or within the ECU circuitry may cause inaccurate signals or failure to detect signals properly.

    4. Timing Chain or Belt Problems: Although less common, issues here can influence sensor readings if the crankshaft movement is abnormal.

    5. Mechanical Damage or Engine Wear: Severe engine damage that affects the crankshaft’s rotation or positioning can trigger this fault.

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How to diagnose trouble code P0335

Diagnosing P0335 requires a systematic approach, starting with basic visual inspections before moving on to electronic testing. Always ensure the vehicle is safely immobilized and the battery is disconnected if necessary for certain steps.

Recommended universal diagnostic steps include:
1. Visual Inspection: Check wiring harnesses and connectors leading to the crankshaft sensor for signs of damage, corrosion, or loose connections.
2. Inspect the Sensor: Physically examine the sensor for damage, dirt, or oil contamination.
3. Test the wiring continuity: Use a multimeter to verify there are no open circuits or shorts between the sensor and ECU.
4. Check Live Data: Connect a diagnostic scanner to observe the crankshaft sensor signal while cranking the engine. Look for ABSENCE of signal or inconsistent data.
5. Compare readings: Cross-reference sensor data with manufacturer specifications or known good values.
6. Test the sensor resistance: Measure resistance values of the sensor; compare with OEM specifications if available.
7. Replace faulty components: If the sensor or wiring is damaged or shows abnormal readings, replace accordingly.

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Possible repairs for trouble code P0335

The appropriate repair depends on the root cause identified during diagnostics, but common fixes include:
– **Replacing the crankshaft position sensor** — Basic repair typically performed by a technician.
– **Cleaning or repairing wiring harnesses and connectors** — Ensures proper electrical continuity. Usually a basic repair but may require professional inspection for extensive wiring damage.
– **Repairing or replacing damaged connectors** — Achieved through cleaning, re-seating, or replacing components.
– **Inspecting and correcting timing chain/belt issues** — Procedural repair requiring advanced tools and expertise.
– **Reprogramming or replacing the ECU** — In case of electronic failure, which is generally a professional task.

Each repair aims to restore proper sensor function and communication, thereby eliminating the fault.

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Vehicles commonly associated with trouble code P0335 in Europe

While the P0335 code is universal across OBD-II compliant vehicles, certain brands and engine families are more frequently affected, especially in Europe. Commonly reported vehicles include:

– **Volkswagen Group**: Beetle, Golf, Passat, Polo with turbocharged petrol engines
– **Ford**: Focus, Fiesta, Mondeo with petrol engines
– **BMW**: Various models with N-series engines
– **Audi**: A3, A4, A6 models with compatible engines
– **Vauxhall/Opel**: Astra, Corsa, Insignia with petrol engines
– **Peugeot/Citroën**: 208, 308, C4 with petrol engines

The likelihood of this fault varies depending on the vehicle’s age, engine type, and maintenance history.

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Frequent mistakes with trouble code P0335

Common errors made during diagnostics and repairs for P0335 include:
– Replacing the sensor prematurely: Without verifying wiring or circuit integrity, leading to unnecessary repairs.
– Ignoring electrical connections: Assuming the sensor is faulty without inspecting wiring harnesses or connectors.
– Not testing live sensor signals: Relying solely on stored codes without real-time data analysis.
– Forgetting to clear codes after repair: Failing to verify if the fault resets or reappears, risking misdiagnosis.
– Overlooking related engine issues: Focusing only on the sensor may neglect underlying problems such as timing variations or engine mechanical faults.

Adopting a thorough diagnostic approach is essential to avoid unnecessary repairs and ensure reliable results.

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FAQ — trouble code P0335

Can this code disappear on its own?
Generally, no. The P0335 code indicates a persistent circuit fault that will remain until diagnosed and repaired. Intermittent faults may temporarily clear but tend to recur if underlying issues are unresolved.

Can I keep driving?
Limited — If the engine runs smoothly, the vehicle can sometimes be driven short distances; however, driving with this fault is risky because it can cause engine stalls or damage. It is safest to have the vehicle inspected promptly.

Why does the code return after clearing?
The fault is typically caused by a hardware or wiring issue that persists beyond the initial fix. If the problem isn’t addressed properly, the code will reappear once the vehicle’s ECU runs its diagnostic checks again.

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