What it means
The ECM detects that the injection pulse on cylinder 3 does not produce the expected combustion result. Pulse width, timing, or quantity drift compared to the bank average.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The engine control module adjusts the injection pulse for cylinder 3 and checks the combustion response. It sets this code when cylinder 3's injection-pulse performance does not match expectations, pointing to possible injector flow drift or a fuel-related combustion problem.
Common causes
Most likely first.
- Injector aged - flow characteristic drifted
- Fuel quality affecting injection result
Symptoms
- Check-engine light may be on
- Rough idle or engine vibration
- Hesitation or reduced power
How to diagnose it
- Save freeze-frame data and review cylinder-specific misfire or contribution readings to determine whether cylinder 3 is the outlier.
- Inspect the cylinder 3 injector connector and wiring for damage, corrosion, loose pins, or fuel leakage.
- Compare cylinder 3 injection-pulse data and combustion contribution with the other cylinders at idle and at the recorded load.
- Consider fuel quality or recent refuelling, particularly if more than one cylinder has changed at the same time.
- If the circuit and fuel checks do not explain the fault, test cylinder 3 injector operation and flow using the manufacturer's procedure.
Common fixes
- Correct unsuitable or contaminated fuel if indicated by the timing and symptoms.
- Secure or repair the cylinder 3 injector connector and wiring.
- Correct fuel contamination if checks show it is affecting injection.
- Replace the cylinder 3 injector if testing confirms out-of-specification performance.
Can I keep driving?
A smooth-running engine may be driven a short distance gently, but avoid high loads while the fault remains. Stop if it develops severe vibration, major power loss, or a flashing warning light, since ongoing misfire can harm the catalytic converter.
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.