Partially blocked or fouled cylinder 12 injector (deposits or debris); Contaminated or poor quality fuel, or a clogged fuel filter or injector inlet screen; Injector electrical fault such as high resistance in the coil or a poor connector pin fit; Low fuel pressure or delivery on the affected bank (pump, regulator or supply fault); Air leak or mechanical issue on the cylinder 12 side that mimics a lean cylinder, such as an intake leak or low compression; Fault in the engine control unit injector driver.

P02C8

Cylinder 12 - Injector Restricted.

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)
C8: FaultThe specific fault in that area

What it means

P02C8 is the generic code for a restricted fuel injector on cylinder 12. The engine control unit has calculated that the cylinder 12 injector is delivering less fuel than commanded, usually by monitoring fuel trims, crankshaft speed variation or the exhaust oxygen sensor response for that cylinder's bank. It only applies to engines with at least twelve cylinders, and the way detection works varies by engine.

Symptoms

Rough idle or misfire felt on one cylinder
Hesitation or flat spot under acceleration
Reduced power and poor fuel economy
Engine warning light on, possibly flashing if misfire is also logged
Lean running on the affected bank
Harder starting or uneven running when cold

Possible causes

Partially blocked or fouled cylinder 12 injector (deposits or debris)likely
Contaminated or poor quality fuel, or a clogged fuel filter or injector inlet screenpossible
Injector electrical fault such as high resistance in the coil or a poor connector pin fitpossible
Low fuel pressure or delivery on the affected bank (pump, regulator or supply fault)possible
Air leak or mechanical issue on the cylinder 12 side that mimics a lean cylinder, such as an intake leak or low compressionrare
Fault in the engine control unit injector driverrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting load, engine temperature and fuel trim values, and check for related misfire or fuel trim codes
Check the long and short term fuel trims on the affected bank at idle and under load to see if the bank is running lean
Inspect the cylinder 12 injector connector and wiring for damage, corrosion, loose pins or water ingress
Measure the injector coil resistance and compare it with the manufacturer's specification for that engine
Check fuel pressure and volume against specification, and inspect the fuel filter where one is fitted
Use a scan tool to run injector balance or cylinder contribution tests, and compare cylinder 12 with the others
Check for intake or vacuum leaks near cylinder 12 and, if the injector tests fine, carry out a compression or leak-down test
Swap the injector with another cylinder where the layout allows and see whether the fault follows the injector

How to fix

Professionally clean the injector, or replace it if flow testing shows it is restricted or out of tolerance
Replace the fuel filter and drain and refill with good quality fuel if contamination is found
Repair or replace damaged injector wiring or connector terminals
Repair the fuel supply fault found, such as a failing pump or pressure regulator, following the model's procedure
Fix any intake leak or mechanical fault found on the cylinder 12 side
Replace the engine control unit only after all wiring and injector checks have confirmed a driver fault

Can I keep driving?

Medium severity

The car can usually be driven gently for a short time, but get it checked soon. A lean or misfiring cylinder can overheat and damage the catalytic converter and affect the engine, so avoid heavy loads and stop if the warning light flashes.

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