P02C6

What it means

P02C6 means the engine control unit has found that the fuel correction it applies to cylinder 12 has reached its maximum limit. It cannot add or remove any more fuel to keep that cylinder's mixture correct. The code does not say whether the limit was reached on the rich or lean side, so live and freeze frame data are needed to find out.

Symptoms

• Engine management warning light on
• Rough running or uneven idle
• Hesitation or poor response under load
• Increased fuel consumption
• Possible misfire codes stored alongside
• Smell of fuel or a lean, flat feel on acceleration

Possible causes

• Fuel injector on cylinder 12 partly blocked, leaking or stickinglikely
• Unmetered air leak near cylinder 12, such as a split intake hose, perished manifold seal or vacuum leaklikely
• Damaged wiring or poor connector contact at the cylinder 12 injectorpossible
• Ignition fault on cylinder 12 (coil or spark plug) causing incomplete combustion and false mixture readingspossible
• Low or uneven fuel pressure or delivery to the bank containing cylinder 12possible
• Exhaust leak or faulty mixture sensor on the bank containing cylinder 12 giving misleading feedbackpossible
• Mechanical problem on cylinder 12, such as low compression or a valve sealing faultrare

How to diagnose

1. Read all stored and pending codes and note any misfire, injector, fuel trim or sensor codes that accompany P02C6.
2. Review freeze frame data and check whether the correction was positive (lean) or negative (rich), and at what load and temperature it set.
3. Inspect the cylinder 12 injector wiring, connector and earth for damage, corrosion, heat damage or oil contamination.
4. Look over the intake system near cylinder 12 for split hoses, loose clamps, cracked manifold seals and vacuum leaks, then smoke test if needed.
5. Compare live short and long term fuel trims for each bank, plus any cylinder-specific trim data, to see if the fault is isolated to cylinder 12 or affects the whole bank.
6. Check fuel pressure and delivery against the manufacturer specification for the engine.
7. Test the cylinder 12 injector for resistance and operation, and swap the coil or plug with another cylinder to see if the fault follows.
8. If the fault stays on cylinder 12, carry out a compression or leak-down test. Cylinder numbering and test access vary by make and engine, so check the correct layout for the vehicle.

How to fix

• Clean or replace the faulty cylinder 12 fuel injector, and renew its seals.
• Repair any intake or vacuum leak and renew perished seals or hoses.
• Repair or replace damaged injector wiring or connectors.
• Replace the faulty ignition coil or spark plug on cylinder 12.
• Correct fuel supply problems, such as a weak pump, blocked filter or faulty pressure regulation, as indicated by the pressure test.
• Repair engine mechanical faults found on cylinder 12 and fix any exhaust leak or faulty sensor on the affected bank.

Can I keep driving?

Nearby codes

• P02C5GenericCylinder 11 - Injector Leaking
• P02C7GenericCylinder 12 - Fuel Trim at Min Limit