Cylinder 9 injector delivering more fuel than commanded (leaking, sticking or worn); Injector wiring or connector fault giving a poor signal at cylinder 9; Fuel pressure too high or a fault in the fuel pressure regulation; Air leak, airflow fault or an exhaust sensor fault skewing the fuel correction on that bank; Mechanical fault in cylinder 9 such as low compression or valve problem affecting the learned correction; Outdated or faulty ECU software or calibration (only where the manufacturer lists it as a known cause).

P02DC

Cylinder 9 Fuel Injector A Offset Learning At Min Limit.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
2: AreaFuel and air metering (injector circuit)
DC: FaultThe specific fault in that area

What it means

P02DC means the engine control unit has learned an offset correction for the cylinder 9 fuel injector (circuit A) and that correction has reached its minimum limit. The ECU adjusts each injector to match the fuel delivery it expects, and here it has run out of room to reduce delivery any further. This code only applies to engines with at least nine cylinders, and how the offset is learned varies by engine and system.

Symptoms

Engine management light on
Rough idle or uneven running, particularly on one bank
Misfire or hesitation under load
Rich running or a smell of unburnt fuel
Poor fuel economy
Possible black smoke on acceleration

Possible causes

Cylinder 9 injector delivering more fuel than commanded (leaking, sticking or worn)likely
Injector wiring or connector fault giving a poor signal at cylinder 9possible
Fuel pressure too high or a fault in the fuel pressure regulationpossible
Air leak, airflow fault or an exhaust sensor fault skewing the fuel correction on that bankpossible
Mechanical fault in cylinder 9 such as low compression or valve problem affecting the learned correctionrare
Outdated or faulty ECU software or calibration (only where the manufacturer lists it as a known cause)rare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting any other injector, misfire or fuel trim codes
Check live fuel trims and injector offset or correction values for all cylinders and compare cylinder 9 with the others
Inspect the cylinder 9 injector connector and wiring for damage, corrosion, heat damage or poor pin tension
Check for misfire counts on cylinder 9 and look for other symptoms on the same bank
Check fuel pressure against the manufacturer's specification at idle and under load
Look for intake air leaks and check airflow and exhaust sensor readings for plausibility
Test the injector electrically and for flow and leakage, following the procedure for that model
Carry out a compression or cylinder leakage test if the injector tests good and the fault persists

How to fix

Replace the cylinder 9 injector if it is found to be leaking, sticking or out of tolerance, then carry out any injector adaptation procedure the manufacturer specifies
Repair or replace damaged wiring or connectors to the injector
Correct fuel pressure faults by repairing or replacing the faulty regulation component as diagnosed
Repair air leaks or replace faulty airflow or exhaust sensors that are skewing fuel correction
Repair any mechanical engine fault found on cylinder 9
Update the ECU software only if the manufacturer identifies an outdated calibration as a cause for this fault

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but book it in soon. A leaking or over-fuelling injector can cause misfires and damage the catalytic converter, and can wash oil from the cylinder wall. If it runs very roughly or the engine light flashes, stop driving.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.