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. P02C6 means the correction for cylinder 12 is at its upper limit: the module keeps giving this cylinder more fuel and still cannot even it out – a sign that the cylinder receives too little fuel or builds too little pressure. 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?You can drive in moderation for a short time. A very lean or very rich mixture can damage the engine or the catalytic converter.
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, possibly misfire
Most likely causes
- Injector of cylinder 12 coked or partly clogged
- Compression loss in this cylinder (valve, rings, leak at injector or glow plug)
- Injector circuit high-resistance or connector
- Petrol: false air at this cylinder's intake (manifold gasket)
- Injector correction code missing or wrong after replacement
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 P02C6 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 2: Fuel injection
- C6: Specific fault in that system
Frequently asked questions
Can I keep driving with code P02C6?
You can drive in moderation for a short time. A very lean or very rich mixture can damage the engine or the catalytic converter.
What causes code P02C6?
The most common causes are: injector of cylinder 12 coked or partly clogged; compression loss in this cylinder (valve, rings, leak at injector or glow plug); injector circuit high-resistance or connector.
Related codes
- P02C7Cylinder 12 - Fuel Trim at Min Limit
- P02C8Cylinder 12 - Injector Restricted
- P02C9Cylinder 12 - Injector Leaking
- P0171System Too Lean Bank 1
- P0296Cylinder 12 Contribution/Balance
- P232ECylinder 12 Fuel Injector A Offset Learning At Max Limit
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.