What it means
The control module detected restricted fuel flow through the cylinder 12 injector.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The control module compares cylinder 12's contribution and injector operation with expected values to assess fuel delivery. It sets P02C8 when the fuel flow attributed to that injector appears restricted, which can reflect an injector blockage or a problem elsewhere in the fuel supply or injector control.
Common causes
Most likely first.
- Clogged or restricted cylinder 12 injector
- Contaminated fuel or deposits in the injector
- Low fuel pressure or restricted fuel supply
- Injector wiring or driver fault
Symptoms
- Check-engine light on
- Rough idle or cylinder 12 misfire
- Reduced power or hesitation
- Poor fuel economy
How to diagnose it
- Use a scan tool to record freeze-frame data and check cylinder-specific misfire or contribution data to see when cylinder 12 began falling behind.
- Inspect the cylinder 12 injector connector and harness for loose pins, corrosion, chafing, or heat damage that could disrupt injector operation.
- Check fuel level and condition, then inspect the accessible fuel supply for restrictions that could reduce delivery to the injectors.
- Compare cylinder 12 injector operation with other cylinders using the scan tool or the vehicle's approved contribution test.
- Test the cylinder 12 injector circuit and driver, and assess injector flow using the manufacturer's procedure before deciding whether the injector is restricted.
Common fixes
- Repair a loose or damaged cylinder 12 injector connector or wiring.
- Correct a restricted fuel filter or supply line if inspection identifies one.
- Clean or replace the cylinder 12 injector if a flow test confirms restriction.
- Repair the injector driver or control fault if circuit testing identifies it.
Can I keep driving?
If the engine runs smoothly and the warning light is steady, limit driving and avoid heavy loads until diagnosed. A persistent cylinder 12 misfire can damage the catalytic converter; stop if the light flashes, power drops sharply, or the engine runs very roughly.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.