P01E1: Cylinder 12 Injection Timing Performance - Over Retarded

What it means

The control module monitors injection timing performance for cylinder 12. It sets this code when injection timing is more retarded than the allowed range.

At a glance

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

How it works

The engine control module monitors injection timing performance for cylinder 12 and compares injector response with the expected timing. This code sets when cylinder 12's injection event is later than the permitted range, pointing to a possible injector or injection-control fault.

Common causes

Most likely first.

1. Injector or injection control fault

How to diagnose it

1. Save freeze-frame data and examine cylinder 12 timing or injector readings to establish when the over-retarded event was detected.
2. Inspect the cylinder 12 injector, connector, and harness for loose fit, corrosion, damage, or fuel leakage.
3. Compare cylinder 12 injector response or contribution with the other cylinders using the scan-tool functions available.
4. Test the cylinder 12 injector wiring and control circuit for opens, shorts, or poor connections using the manufacturer's procedure.
5. If the circuit is sound, evaluate injector operation and fuel delivery against the manufacturer's specification.

Common fixes

• Repair a damaged cylinder 12 injector connector or wiring.
• Correct any verified fuel delivery problem.
• Clean or replace a sticking or faulty cylinder 12 injector.
• Repair the cylinder 12 injector driver or control circuit if tests confirm a fault.

Can I keep driving?

If the warning light is steady and the engine runs normally, limit driving to gentle trips and avoid heavy loads. Stop if rough running or power loss develops, as continued poor combustion can increase emissions and damage exhaust components.