What it means
During cold start, the measured fuel injection quantity for group B 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 a cold start, the engine control module estimates fuel delivery for injection group B and compares it with the calibrated cold-start range. This code sets when group B delivers less fuel than expected while the engine is cold. Restricted injectors or low rail pressure can make cold starting and running worse.
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
- After the engine has cooled, record freeze-frame data and observe cold-start fuel-quantity and misfire data to confirm the fault occurs during the cold-start phase.
- Inspect group B injector wiring and connectors for loose, corroded, or damaged contacts that could affect cold-start operation.
- Check for fuel leaks and review available rail-pressure data during the cold-start conditions shown in the freeze frame.
- Measure fuel rail pressure during a cold start and compare it with the manufacturer's specification.
- If pressure and wiring are sound, test group B injectors for restricted flow using the manufacturer's specified procedure.
Common fixes
- Repair damaged or poorly seated group B injector wiring and connections.
- Correct a fuel supply fault if cold-start rail pressure is below the manufacturer's specification.
- Clean or replace restricted group B injectors as testing indicates.
- Confirm cold-start fuel-quantity and misfire readings are normal after repair.
Can I keep driving?
Avoid driving while the engine is misfiring or struggling to run after a cold start, since continued misfire can damage the catalytic converter. If the engine stalls or will not start reliably, have the fault addressed before relying on the vehicle.
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.