Cause
Carbon deposits in the combustion chamber
Deposits on the piston crown and chamber roof, which raise compression and hold heat. They make the engine more prone to knocking than it was designed to be, so the module retards timing to protect it and the car goes flat and thirsty without ever making a noise.
Short journeys and long service intervals build them; sustained higher-load running helps clear them.
Typically a moderate job.
Codes this can cause (17)
Codes where this is a likely explanation first, rather than merely a possible one.
- P01D0 Cylinder 3 Injection Timing Performance - Over Advanced Likely for this code Moderate
- P2336 Cylinder 1 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2337 Cylinder 2 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2338 Cylinder 3 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2342 Cylinder 7 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2343 Cylinder 8 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2344 Cylinder 9 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2345 Cylinder 10 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2346 Cylinder 11 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P2347 Cylinder 12 Above Knock/Combustion Vibration Sensor Threshold Likely for this code High
- P01CC Cylinder 1 Injection Timing Performance - Over Advanced Moderate
- P01CE Cylinder 2 Injection Timing Performance - Over Advanced Moderate
- P01D4 Cylinder 5 Injection Timing Performance - Over Advanced Moderate
- P01D6 Cylinder 6 Injection Timing Performance - Over Advanced Moderate
- P2339 Cylinder 4 Above Knock/Combustion Vibration Sensor Threshold High
- P2340 Cylinder 5 Above Knock/Combustion Vibration Sensor Threshold High
- P2341 Cylinder 6 Above Knock/Combustion Vibration Sensor Threshold High
Information, not instruction
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