What it means
During cold start, the measured fuel injection quantity for group C is above the calibrated cold-start window. Cold-start strategy or injector flow drift.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
During cold starting, the engine control module estimates fuel delivered by injection group C and compares it with the cold-start operating window. This code sets when the estimated quantity for group C is higher than expected during that strategy, which may indicate a leaking injector or excessive rail pressure.
Common causes
Most likely first.
- Injector leaking
- Fuel rail pressure high
Symptoms
- Check-engine light
- Rough cold start or misfire
- Longer cranking when the engine is cold
- Fuel odor or dark exhaust
How to diagnose it
- Record freeze-frame data and coolant temperature, then compare group C injection quantity with other groups during a cold start.
- Check for cold-start misfire, fuel odor, or dark exhaust and note whether symptoms improve as the engine warms.
- Inspect group C injectors and their connectors and wiring for signs of leakage, damage, or poor connections.
- Compare actual and commanded fuel rail pressure during cold cranking with the manufacturer's specification.
- If pressure is correct, test group C injectors for leakage or excessive flow using the manufacturer's procedure.
Common fixes
- Repair damaged or poorly connected group C injector wiring.
- Correct a confirmed fuel rail pressure control fault.
- Replace a group C injector confirmed to leak or over-deliver during cold operation.
- Resolve a verified cold-start measurement or calibration issue using the manufacturer's procedure.
Can I keep driving?
Avoid repeated cold starts and unnecessary driving if there is fuel odor, dark exhaust, or persistent rough running; excess fuel can raise emissions and damage exhaust after-treatment components. Stop if fuel is visibly leaking or the engine runs severely unevenly.
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.