Cause
Injector fitted without entering its calibration code
An injector was replaced and its calibration code never programmed into the module, so the module continues applying the previous injector's correction — or none.
This is the commonest reason a diesel runs badly immediately after injector work, and the reason it costs money is that it looks exactly like a faulty new part. Uneven idle, a harder knocking note from the affected cylinder, smoke and poor economy are precisely what a worn injector produces, so the natural conclusion is that the replacement is defective. Fitting a second one changes nothing, because it will not be coded either.
Nothing is broken. A step in the job was not done. Coding takes a scan tool and a few minutes, and nothing about fitting the injector accomplishes it automatically.
A related trap catches reconditioned injectors specifically: a remanufactured injector is flow-tested again after rebuild and issued a new code, supplied on the reconditioner's paperwork. The code stamped on its body is the original one and is no longer correct — entering it produces the same fault as entering nothing.
Beyond the running quality, there is a reason not to live with it. An uncorrected injector may be over-delivering, putting more fuel into one cylinder than the module believes on every mile driven, at higher local temperature and pressure. That is a slow risk to the piston rather than an immediate one, but it is real.
Typically specialist work. Needs equipment or training most home workshops do not have.
Codes this can cause (37)
Codes where this is a likely explanation first, rather than merely a possible one.
- P01CD Cylinder 2 Injection Timing Performance - Over Retarded Likely for this code Moderate
- P020A Cylinder 1 Injection Timing Likely for this code Moderate
- P020B Cylinder 2 Injection Timing Likely for this code Moderate
- P02CC Cylinder 1 Fuel Injector A Offset Learning At Min Limit Likely for this code High
- P02CD Cylinder 1 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P02CE Cylinder 2 Fuel Injector A Offset Learning At Min Limit Likely for this code High
- P02CF Cylinder 2 Fuel Injector A Offset Learning At Max Limit Likely for this code High
- P2690 Cylinder 5 Injector Data Incompatible Likely for this code Moderate
- P2691 Cylinder 6 Injector Data Incompatible Likely for this code Moderate
- P2692 Cylinder 7 Injector Data Incompatible Likely for this code Moderate
- P2693 Cylinder 8 Injector Data Incompatible Likely for this code Moderate
- P2694 Cylinder 9 Injector Data Incompatible Likely for this code Moderate
- P2695 Cylinder 10 Injector Data Incompatible Likely for this code Moderate
- P2B10 Cylinder 1 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B12 Cylinder 2 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B14 Cylinder 3 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B16 Cylinder 4 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B18 Cylinder 5 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B1A Cylinder 6 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B1C Cylinder 7 Injection Pulse Offset Not Learned Likely for this code Moderate
- P2B1E Cylinder 8 Injection Pulse Offset Not Learned Likely for this code Moderate
- U0306 Software Incompatibility With Fuel Injector Control Module Likely for this code High
- P01D6 Cylinder 6 Injection Timing Performance - Over Advanced Moderate
- P020C Cylinder 3 Injection Timing Moderate
- P020D Cylinder 4 Injection Timing Moderate
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.
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