What it means
During cold start, the measured fuel injection quantity for group B 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 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's measured quantity is higher than expected while the engine is cold. A leaking injector or excessive rail pressure can cause rough cold running, fuel odor, or dark exhaust.
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
- After the engine has cooled, record freeze-frame data and check cold-start fuel-quantity and misfire readings to confirm when group B exceeds its expected range.
- Inspect group B injector connectors and wiring for damage or poor contacts that could affect commanded fuel delivery.
- Check for fuel odor, visible leaks, or dark exhaust during a cold start before continuing with tests.
- Measure fuel rail pressure during the cold-start conditions indicated by the freeze frame and compare it with the manufacturer's specification.
- If pressure and wiring are sound, test group B injectors for leakage or excess flow using the manufacturer's specified procedure.
Common fixes
- Repair damaged or poorly connected group B injector wiring.
- Correct a fuel-pressure control fault if cold-start rail pressure is above the manufacturer's specification.
- Replace a leaking group B injector identified by testing.
- Confirm cold-start fuel-quantity data and exhaust behavior after repair.
Can I keep driving?
Avoid extended driving if cold starts produce a strong fuel smell, dark exhaust, or persistent misfire; excess fuel can increase emissions and damage the catalytic converter. Stop if you find a fuel leak.
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.