Diagnostic trouble code P1331 is a manufacturer-specific powertrain fault code. Because it is manufacturer-specific, its exact definition depends entirely on the vehicle make, model, and application.
Exact vehicle application must be verified before diagnosis. The code identifies a detected condition in a specific subsystem, but further testing is required to identify the root cause.
Quick Navigation
Key Takeaways
- P1331 is a manufacturer-specific code, meaning its definition varies between automakers like Volkswagen, Audi, BMW, and Porsche.
- On VW and Audi applications, it indicates that the knock control limit for cylinder 7 has been attained.
- On BMW and Mini applications, it points to a camshaft position sensor B timing reference out of range fault.
- On Porsche applications, it may indicate an inlet camshaft output stage fault on bank 2.
- Diagnosis requires verifying the exact factory definition and testing the relevant knock sensor, ignition, or camshaft circuits.
P1331 Code Description and Implications
Because P1331 is manufacturer-specific, there is no single universal definition. This trouble code identifies a detected condition, but the exact monitored system depends on the vehicle make and model.
Some Volkswagen and Audi applications: P1331 indicates a “Cylinder 7 Knock Control Limit Attained” fault. The engine control module detects that the knock control system has reached its maximum retard limit for cylinder 7.
Some BMW and Mini applications: P1331 indicates a “Camshaft Position Sensor B Timing Reference Out of Range” fault. The module detects that the camshaft timing signal is outside the expected parameters.
Some Porsche applications: P1331 may indicate an “Inlet Camshaft Output Stage Bank 2” fault, relating to the variable valve timing control circuit.
Common Causes of the P1331 Code
For VW and Audi applications, possible causes include low-quality or incorrect octane fuel, excessive carbon buildup in the combustion chamber, a failing knock sensor, or damaged knock sensor wiring.
For BMW and Mini applications, causes may involve a failing camshaft position sensor, a stretched timing chain, a faulty variable valve timing solenoid, or damaged sensor wiring.
For Porsche applications, causes can include a failing variable valve timing solenoid, damaged wiring in the camshaft output stage circuit, or poor electrical connections.
Symptoms Associated With P1331
On VW and Audi applications with a knock control limit fault, symptoms can include audible engine knocking or pinging, reduced engine power, and an illuminated Check Engine Light.
On BMW and Mini applications with a camshaft position fault, symptoms may include rough idling, engine misfires, poor acceleration, and a no-start condition.
On Porsche applications, symptoms can include reduced engine performance and illuminated dashboard warning lights.
Diagnosing the P1331 Trouble Code
Diagnosis must begin by confirming the exact factory definition for the specific make, model, and year.
For VW and Audi applications, technicians inspect the knock sensor wiring, verify the fuel quality, check for carbon buildup, and monitor the knock sensor retard values using a scan tool.
For BMW and Mini applications, technicians test the camshaft position sensor circuits, inspect the timing chain for stretch, and verify the variable valve timing solenoid operation.
For Porsche applications, technicians test the inlet camshaft output stage circuits and verify the solenoid operation.
Repairing the P1331 Issue
If a knock control limit fault is confirmed on a VW or Audi, the fuel must be replaced with the correct octane, carbon deposits cleaned, or the knock sensor repaired.
If a camshaft position fault is confirmed on a BMW or Mini, the sensor, timing chain, or variable valve timing solenoid must be replaced as diagnosed.
If an inlet camshaft output stage fault is confirmed on a Porsche, the solenoid or damaged wiring must be replaced or repaired.
Cost Considerations for P1331 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Replacing a knock sensor or camshaft position sensor may require minimal labor depending on accessibility.
Conversely, replacing a stretched timing chain or cleaning severe internal carbon buildup requires significant engine disassembly and labor.
Prevention Strategies for Future Occurrences
Some mechanical failures cannot be reliably prevented.
Using fuel with the manufacturer-recommended octane rating can help prevent excessive engine knock on applications monitoring the knock control limit.
Performing regular oil changes with the correct oil viscosity helps maintain variable valve timing components and prevents timing chain wear on applicable engines.
Troubleshooting Tips and Best Practices
Never assume P1331 is a universal knock sensor code. Always verify the exact definition for the specific vehicle before purchasing parts.
Do not ignore related codes. A knock control fault may appear alongside specific cylinder misfire codes, while a camshaft position fault may appear alongside crankshaft position sensor codes.
Check for technical service bulletins applicable to your exact vehicle application, as manufacturers frequently release updated sensors or revised software calibrations for recurring faults.
More OBD-II Codes
| P1325 | P1336 | P0325 | P0300 |
| P1324 | P1344 | P0330 | P0301 |
| P1323 | P1345 | P0332 | P0302 |
| P1322 | P1346 | P0340 | P0303 |
| P1321 | P1347 | P0011 | P0016 |
| P1320 | P1348 | P0014 | P0017 |
Frequently Asked Questions
Is P1331 a generic or manufacturer-specific code?
No. P1331 is a manufacturer-specific code. Its exact definition varies significantly between automakers, so the factory service information for the specific vehicle must be consulted.
Can I drive my car with a P1331 code?
It depends on the application. If P1331 indicates a knock control limit fault, continued driving may cause engine damage. If it is a camshaft fault, the vehicle may stall.
Will disconnecting the battery clear the P1331 code?
Disconnecting the battery may temporarily clear the code, but it does not repair the underlying electrical or mechanical fault. The code will return once the monitor runs again.
Can low-quality fuel cause a P1331 code?
On VW and Audi applications, using fuel with an octane rating lower than recommended can cause excessive engine knock, triggering the control limit fault for the affected cylinder.
Does P1331 always mean the knock sensor is bad?
No. While a failing knock sensor is a cause on specific applications, the code can also indicate low-quality fuel, carbon buildup, or a camshaft position sensor fault on other vehicles.
What Should You Do About the P1331 Code?
Confirm the exact factory definition and diagnostic procedure for your specific vehicle application. Because P1331 is manufacturer-specific, identifying whether it relates to a knock control limit fault or a camshaft sensor is mandatory.
Follow the applicable manufacturer diagnostic steps to test the relevant system and components. Once the root cause is confirmed, complete the necessary repairs and verify that the system operates correctly.
