P02C9: Cylinder 12 - Injector Leaking

What it means

The control module monitors fuel delivery associated with the cylinder 12 injector and sets this code when it detects injector leakage. The code identifies a leak condition but does not by itself identify whether the injector, its seal, or another part of the fuel system is responsible.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The control module monitors fuel delivery associated with the cylinder 12 injector and detects signs that fuel continues to enter when it should not. P02C9 identifies a leak condition, but the leak may be at the injector, its seal, or another part of the fuel system.

Common causes

Most likely first.

1. Leaking cylinder 12 injector or injector seal
2. Injector stuck partly open
3. Excessive fuel pressure
4. Injector control fault

Symptoms

• Check-engine light on
• Rough idle or misfire
• Fuel smell or dark exhaust smoke
• Poor fuel economy

How to diagnose it

1. Record freeze-frame data and check cylinder 12 misfire and fuel-trim information to see whether the fault occurs at idle, under load, or after shutdown.
2. With the engine off and cool, inspect around the cylinder 12 injector and fuel rail for wetness or fuel odor; follow fuel-system safety precautions.
3. Inspect the cylinder 12 injector seal, connector, and harness for damage or signs of fuel leakage.
4. Check fuel pressure and pressure retention using the manufacturer's procedure to determine whether pressure is excessive or fuel is leaking down.
5. If external leaks and pressure problems are ruled out, test injector control and have cylinder 12 injector leakage evaluated using the vehicle's approved procedure.

Common fixes

• Replace a leaking cylinder 12 injector seal if the injector and sealing surface are serviceable.
• Replace the cylinder 12 injector if it leaks or remains partly open.
• Repair a fuel-pressure fault if testing finds pressure above the manufacturer's specification.
• Repair the injector control circuit if tests show the injector is being commanded incorrectly.

Can I keep driving?

Avoid driving if you can smell fuel, see a leak, or notice dark smoke or a severe misfire; shut the engine off because leaked fuel can create a fire risk and may damage the catalytic converter. If there are no leak signs and the engine runs normally, drive only a short distance for diagnosis.