What it means
During cold start, the measured fuel injection quantity for group D is below 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 D and checks it against the cold-start operating window. This code sets when group D's estimated quantity is lower than expected during cold-start operation, possibly because its injectors are restricted or rail pressure is low.
Common causes
Most likely first.
- Injectors partially clogged
- Fuel rail pressure low
Symptoms
- Check-engine light
- Rough cold start or misfire
- Longer cranking when the engine is cold
- Reduced power until the engine warms
How to diagnose it
- Record freeze-frame data and coolant temperature, then compare group D injection quantity with the other groups during a cold start.
- Check cold-start misfire or cylinder balance data to see whether rough running is concentrated in cylinders served by group D.
- Inspect group D injector connectors and wiring for corrosion, damage, or loose connections.
- Compare actual and commanded fuel rail pressure during cold cranking and warm-up with the manufacturer's specification.
- If pressure is within specification, test group D injector flow or balance using the manufacturer's procedure.
Common fixes
- Repair a damaged or poorly connected group D injector circuit.
- Correct a confirmed low fuel rail pressure fault.
- Clean or replace a group D injector confirmed to have restricted flow.
- Correct a verified cold-start measurement or calibration issue using the manufacturer's procedure.
Can I keep driving?
Gentle driving may be possible if the engine runs smoothly after warming, but avoid driving with persistent misfire or severe power loss. Repeated cold-start misfires can increase emissions and may damage the exhaust after-treatment system.
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.