Cause
Contaminated or poor quality fuel
Water, debris, biological growth or off-specification fuel in the tank. On a diesel the property that matters is cetane number — how readily the fuel ignites under compression. Low-cetane fuel ignites more slowly, so combustion peaks later than the module predicted from a perfectly correct injection event, and the result is logged as an injection timing error on a mechanically sound engine.
Water is the more damaging half. Modern high pressure fuel systems rely on the fuel itself to lubricate pump and injector clearances, so water displacing that film causes rapid wear, and it also corrodes and narrows injector nozzles.
The timing of the complaint is the diagnostic. A fault that appeared immediately after a fill-up points here far more strongly than at any component, which is why where and when the tank was last filled is worth asking about before parts are ordered. Check the water separator and the filter's age; replacing an injector while leaving contaminated fuel in the tank simply feeds the new one the same problem.
Typically a moderate job.
Codes this can cause (19)
Codes where this is a likely explanation first, rather than merely a possible one.
- P026B Injection Timing Performance Likely for this code Moderate
- P02CD Cylinder 1 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02CF Cylinder 2 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02D1 Cylinder 3 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02D3 Cylinder 4 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02D5 Cylinder 5 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02D7 Cylinder 6 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P009E Fuel Pressure Relief Control Performance/Stuck Off Moderate
- P01CB Cylinder 1 Injection Timing Performance - Over Retarded Moderate
- P01CC Cylinder 1 Injection Timing Performance - Over Advanced Moderate
- P01CE Cylinder 2 Injection Timing Performance - Over Advanced Moderate
- P01D0 Cylinder 3 Injection Timing Performance - Over Advanced Moderate
- P01D2 Cylinder 4 Injection Timing Performance - Over Advanced Moderate
- P01D4 Cylinder 5 Injection Timing Performance - Over Advanced Moderate
- P01D6 Cylinder 6 Injection Timing Performance - Over Advanced Moderate
- P050B Cold Start Ignition Timing Performance Moderate
- P050D Cold Start Rough Idle Moderate
- P22FA NOx Sensor Performance - Slow Response High to Low Bank 1 Sensor 1 Moderate
- P2B95 Cold Start Injection Pulse Performance Moderate
Information, not instruction
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