What it means
During cold start, the ECM detects that the injection pulse on cylinder 8 does not produce the expected combustion result. Cold-start specific pulse calibration deviates from learned values.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The ECM adjusts cylinder 8's injector pulse during cold starting and checks engine-speed changes to judge whether that cylinder is contributing as expected. This code sets when the cold-start compensation for cylinder 8 falls outside the learned range, which can happen if its injector delivers or atomizes fuel poorly while cold.
Common causes
Most likely first.
- Injector behaviour drifts at low temperature
- Poor fuel atomization at cold start
Symptoms
- Rough idle just after a cold start
- Engine stumble or vibration when cold
- Check-engine light
How to diagnose it
- Check freeze-frame data and note coolant temperature, engine speed, and whether the fault occurred during a cold start.
- After the engine has cooled, compare cylinder contribution or misfire data at startup with the other cylinders to see whether cylinder 8 is the outlier.
- Inspect cylinder 8's injector connector and nearby wiring for looseness, corrosion, damage, or signs of fuel leakage.
- Check for related misfire, injector, or fuel-pressure codes that could point to a shared cause.
- If the fault is repeatable, have cylinder 8's injector delivery and cold-start spray behaviour assessed using the vehicle manufacturer's procedure.
Common fixes
- Repair a loose, damaged, or corroded cylinder 8 injector connection or wire.
- Correct a fuel-quality or fuel-contamination issue if inspection confirms one.
- Replace the cylinder 8 injector if testing confirms poor cold delivery or atomization.
- Repair a fuel-pressure problem if measured pressure is outside the manufacturer's specification.
Can I keep driving?
A brief trip may be reasonable if the engine runs smoothly once warm and the check-engine light is steady. Avoid hard acceleration while it is stumbling; continued misfire can increase emissions and damage the catalytic converter, and a flashing light or severe shaking calls for stopping safely.
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.