P02DD - Cylinder 6 Injector Fuel Learning at Max Limit

P02DD indicates that the Engine Control Unit (ECU) has exceeded its maximum adaptive learning limit for the fuel injector on cylinder 6. The ECU monitors the crankshaft speed fluctuations (acceleration) to balance cylinder contribution. When the ECU detects that cylinder 6 is underperforming, it increases the injector pulse width (on-time). If the compensation required exceeds a calibrated threshold, P02DD is stored. This typically signals a lean condition specifically affecting cylinder 6, which cannot be corrected through standard adaptation logic. This fault will often trigger a derate mode to protect aftertreatment components like the DPF from thermal stress.