P02CF: Cylinder 2 Fuel Injector A Offset Learning At Max Limit

What does P02CF mean?

The engine module learns a small-quantity correction for each injector: on overrun it gives one injector a tiny test injection (GM about 1.5 mm³), measures the resulting crankshaft acceleration and corrects the injector's activation time per rail pressure step. P02CF means the learned correction for cylinder 2 has reached its upper limit at at least one pressure step: the injector needs much more activation time than nominal – it delivers too little or opens late, for example from coking. GM diesels set it at limits of roughly ±66–182 µs after two trips. Older GM calibrations (LML) use only this code of the pair, for both directions. It is documented on GM's 6.6 litre L5P and 2.8 litre diesels – on the 2.8 a worn drive belt caused it to return after injector replacement – and on Land Rover's 5.0 V8 petrol, where a software update is the first step. It differs from P01CD (over retarded), which some systems derive from the same learning.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Often nothing noticeable; possibly rough idle or knocking
• Possibly smoke or loss of power

Common causes

• High Injector of cylinder 2 coked or worn (delivers too little)
• Medium Engine software (update available for some models)
• Medium Injector correction code not or wrongly programmed after replacement
• Low Disturbed crankshaft signal (worn drive belt, tone wheel, dual-mass flywheel)
• Low Low compression on this cylinder

Likelihood is a general estimate across vehicles; your make and model may differ.