Leaking or stuck-open fuel injector on cylinder 11; Faulty or contaminated oxygen or air-fuel ratio sensor on the bank containing cylinder 11, giving a false lean reading; Wiring or connector fault on the cylinder 11 injector or its bank sensor circuit; Excessive fuel pressure on that bank, for example from a faulty regulator or pressure sensor (depends on the fuel system design); Purge valve or crankcase ventilation fault adding extra fuel vapour to that cylinder bank; Outdated or faulty ECU calibration affecting cylinder fuel trim; Mechanical fault in cylinder 11 such as poor compression changing the combustion and exhaust reading.

P02C3

Cylinder 11 - Fuel Trim 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)
C3: FaultThe specific fault in that area

What it means

P02C3 means the engine control unit has found that the fuel trim correction for cylinder 11 has reached its minimum limit, so it is pulling as much fuel as it can from that cylinder. The ECU saw that cylinder running richer than expected, or its individual cylinder balance reading pointing to excess fuel, and could not trim any further. This code only applies to engines with at least 11 cylinders and individual cylinder fuel trim control, so it will be rare outside large V12 and similar engines.

Symptoms

Check engine light on
Rough idle or misfire feel, mainly on large multi-cylinder engines
Smell of unburnt fuel from the exhaust
Increased fuel consumption
Hesitation or uneven power delivery under load
Black smoke or sooty exhaust in severe cases

Possible causes

Leaking or stuck-open fuel injector on cylinder 11likely
Faulty or contaminated oxygen or air-fuel ratio sensor on the bank containing cylinder 11, giving a false lean readingpossible
Wiring or connector fault on the cylinder 11 injector or its bank sensor circuitpossible
Excessive fuel pressure on that bank, for example from a faulty regulator or pressure sensor (depends on the fuel system design)possible
Purge valve or crankcase ventilation fault adding extra fuel vapour to that cylinder bankrare
Outdated or faulty ECU calibration affecting cylinder fuel trimrare
Mechanical fault in cylinder 11 such as poor compression changing the combustion and exhaust readingrare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including fuel trims, load and engine temperature
Check for related codes such as other cylinder trim codes, misfire codes or sensor faults, and deal with those first
Inspect the injector wiring, connectors and earths for cylinder 11 and the sensors on its bank for damage, corrosion or water
Watch live short and long term fuel trims and the air-fuel ratio sensor readings for the relevant bank to see whether the rich condition is real
Check fuel pressure and compare with the manufacturer's specification, noting the procedure varies by engine
Test the cylinder 11 injector for leakage, resistance and spray pattern, and compare with a neighbouring cylinder
Check the purge valve and crankcase ventilation operation for extra fuel entering that bank
Carry out a compression or leak-down test on cylinder 11 if the fuel side checks out

How to fix

Replace or professionally clean and test the faulty cylinder 11 fuel injector
Repair damaged wiring, connectors or earths on the injector or bank sensor circuit
Replace a faulty oxygen or air-fuel ratio sensor once it has been confirmed as inaccurate
Correct the fuel pressure fault by replacing the faulty regulator, sensor or pump component as the system requires
Repair a stuck purge valve or ventilation fault
Update the ECU calibration only if the manufacturer lists an outdated one as a known cause for this fault

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but a rich cylinder can wash oil from the bore and overload the catalytic converter, so get it checked soon. Stop driving if the engine misfires badly, the check engine light flashes or you smell strong fuel.

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