P01D4: Cylinder 5 Injection Timing Performance - Over Advanced
What to do
Ask how many cylinders are affected before agreeing to any repair. One cylinder means that injector; several together means something shared, like fuel or timing. That distinction decides whether this is a small job or a large one.
If an injector has to come out, ask what the others' leak-back figures are and what the labour is to reach them. On a six or eight cylinder engine, doing a worn set together is much cheaper than returning for each in turn.
Say whether the engine knocks or sounds harsh under load, which fits this fault.
Do not leave it running like this, since early combustion loads the piston and bearings at the wrong point.
What this code means
Combustion on cylinder 5 is happening earlier than the module commanded.
The causes are the over-advanced family's — a leaking injector, an inaccurate pilot injection, over-volatile fuel, or hot spots — with the bank-level reading that cylinder 5 invites on a V engine.
One thing is worth stating clearly at this point in the family, because it is easy to lose sight of across eleven similar codes. An advanced burn on a single cylinder is almost never a timing reference problem. The chain, the belt, the crank sensor and the cam sensor are all shared — anything wrong with them moves every cylinder together. So a single-cylinder over-advance is confined to that cylinder's injector or that cylinder's condition, and time spent checking the timing drive is time wasted.
Where several cylinders are advanced together, the opposite applies and the timing reference becomes the first thing to check rather than the last.
That single rule — shared hardware moves everything, single-cylinder faults are local — resolves most of the confusion this family generates.
On a larger engine the practical question remains access. If an injector must come out, ask what the labour is to reach the others and what their leak-back figures look like, because doing a drifting set together is far cheaper than doing them one at a time.
Likely causes
Start here
- Worn or leaking fuel injectors · specialist
Less common
- Incorrect injection timing · specialist
- Carbon deposits in the combustion chamber · specialist
- Contaminated or poor quality fuel · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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