These codes belong to an individual-cylinder fuel correction: a diesel's cylinder balance control measures each cylinder's crankshaft acceleration and adjusts its injection quantity; on petrol engines a cylinder-selective mixture control does the same. CARB requires the system to report when such a correction has used up its range or one cylinder causes an imbalance. P02C8 means the module attributes the deviation of cylinder 12 to an injector delivering too little – deposits or a sticking nozzle needle. Cylinder 12 only exists on engines with twelve or more cylinders. GM and Ford use other codes for this (P0263 ff, P219A ff); no manufacturer document describing this code with thresholds was found, so the description follows CARB and published patents.
Medium severity. Can I keep driving?Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.
Cylinder 12 is numbered according to the manufacturer: check your engine's manual before working on it.
Symptoms
- Check engine light on
- Rough idle, vibration
- Lack of power, higher consumption or smoke
Most likely causes
- Deposits or coking at the nozzle of cylinder 12
- Nozzle needle sticking
- Contaminated fuel or water
- Injector circuit high-resistance
- Compression loss mimicking low output
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P02C8 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 2: Fuel injection
- C8: Specific fault in that system
Frequently asked questions
Can I keep driving with code P02C8?
Drive as little as possible and go to a repair shop. If you smell fuel or the engine is shaking badly, do not keep driving.
What causes code P02C8?
The most common causes are: deposits or coking at the nozzle of cylinder 12; nozzle needle sticking; contaminated fuel or water.
Related codes
- P02C6Cylinder 12 - Fuel Trim at Max Limit
- P02C7Cylinder 12 - Fuel Trim at Min Limit
- P02C9Cylinder 12 - Injector Leaking
- P0296Cylinder 12 Contribution/Balance
- P232ECylinder 12 Fuel Injector A Offset Learning At Max Limit
- P0212Cylinder 12 Injector A Circuit/Open
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.