P02D4: Cylinder 5 Fuel Injector A Offset Learning At Min Limit
What to do
Ask for the trim figures to be read for every cylinder and grouped by bank. On a V engine each bank often has its own fuel pressure sensor, and if all the cylinders on one bank are trimmed the same way, the fault is that bank's pressure reading rather than its injectors. That distinction can be the difference between one sensor and three injectors.
Ask whether any fuel pressure codes are stored, since those would point the same way.
Check the oil level and smell it. Over-delivery washes diesel into the sump and a rising level needs prompt attention.
Ask for a leak-back test before any injector is replaced.
What this code means
The correction the module applies to cylinder 5's injector has reached the bottom of its adjustment range.
Cylinder 5 over-delivers and the trim has run out.
A cylinder 5 code means a six-cylinder engine or larger, which usually means two banks — and two banks can mean two of everything. On many V engines each bank has its own rail section, its own pressure sensor and sometimes its own high pressure supply. A pressure reference that reads differently on one bank pushes every injector on that bank the same way.
So read the trims bank by bank rather than cylinder by cylinder. Three injectors on one bank all trimmed hard in the same direction, with the other bank sitting normally, is a bank-level supply or sensor fault — not three worn injectors.
This is the single most expensive mistake available in this family, because three injectors on a large engine is a very substantial bill for a fault that lives in a pressure sensor.
Where the trims are scattered rather than grouped by bank, the ordinary causes apply — wear, a leaking injector, or a calibration code never entered. The leak-back test remains the measurement that settles it, and on a multi-bank engine it should be read per bank as well as per cylinder.
Likely causes
Start here
- Worn or leaking fuel injectors · specialist
Less common
- Faulty fuel rail pressure sensor · moderate
- Injector fitted without entering its calibration code · specialist
- Failed fuel injector · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
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
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P02D4.