What it means
Injection timing performance for cylinder 1 is more advanced than the expected range.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The injection control system meters fuel through the injector for cylinder 1, and the control module checks whether its timing response follows the command. This code sets when cylinder 1 injection is more advanced than the allowed range, which can involve the injector, its control circuit, or fuel delivery.
Common causes
Most likely first.
- Injector wear, sticking, or restricted flow
- Fault in cylinder 1 injector wiring or connector
- Injector driver or control circuit fault
- Fuel pressure or delivery problem affecting injector response
Symptoms
- Check engine light on
- Rough idle or vibration
- Reduced power or uneven acceleration
- Increased fuel consumption
How to diagnose it
- Review freeze-frame data and cylinder-specific live data to confirm the timing deviation is associated with cylinder 1 and note when it occurs.
- Inspect the cylinder 1 injector connector and wiring for corrosion, loose terminals, or damage that could affect injector control.
- Check for related injector, misfire, or fuel pressure codes to see whether the timing issue is isolated to cylinder 1 or part of a wider problem.
- Test the cylinder 1 injector control circuit and driver response using the manufacturer's specified procedure.
- If the circuit is sound, assess cylinder 1 injector operation and fuel delivery against the manufacturer's specifications.
Common fixes
- Reconnect a loose cylinder 1 injector connector and secure the wiring.
- Repair damaged or corroded wiring in the cylinder 1 injector circuit.
- Clean or replace a confirmed sticking or faulty cylinder 1 injector.
- Repair a confirmed injector driver or control circuit fault.
- Correct a fuel pressure or delivery problem affecting injector response.
Can I keep driving?
If the engine is running smoothly, drive gently and avoid heavy load because incorrect cylinder 1 injection timing can contribute to roughness, power loss, and increased fuel use. Stop if it misfires severely or stalls.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.