What it means
Injection timing on cylinder 1 lags more than allowed. Often injector wear or response drift.
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 monitors whether its timing response follows the commanded timing. This code sets when cylinder 1 injection is more delayed than allowed, which can result from a slow or restricted injector, an electrical fault, or a fuel delivery problem.
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 for roughness or timing deviation to confirm the fault centers on cylinder 1.
- Inspect the cylinder 1 injector connector and wiring for looseness, corrosion, damaged insulation, or signs of poor contact.
- Check for related misfire, fuel pressure, and injector circuit codes that could help distinguish an injector problem from a broader delivery fault.
- Test the cylinder 1 injector circuit and control response using the manufacturer's specified procedure.
- If the electrical checks pass, assess cylinder 1 injector operation and fuel delivery against the manufacturer's specifications.
Common fixes
- Reconnect a loose cylinder 1 injector connector and secure its wiring.
- Repair damaged or corroded wiring in the cylinder 1 injector circuit.
- Clean or replace a confirmed restricted or sticking 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?
Gentle driving may be possible if the engine runs smoothly, but avoid heavy acceleration because delayed cylinder 1 fueling can cause roughness, power loss, and higher 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.