What it means
The ECM detects that the injection pulse on cylinder 6 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 ECM assesses cylinder 6's response to its injector pulse and compares it with the other cylinders on the same bank. P2B05 sets when cylinder 6's injection performance is outside the expected pattern, potentially because injector flow has drifted or fuel quality is affecting combustion.
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 check scan-tool misfire or fuel-balance readings to confirm whether cylinder 6 is the outlier.
- Check the fuel and recent refuelling history, especially if the hesitation or roughness began soon after filling up.
- Inspect the cylinder 6 injector connector and harness for damage, corrosion, or a poor connection.
- Compare cylinder 6's injector command and contribution with the other cylinders under similar operating conditions.
- If evidence remains specific to cylinder 6, test injector flow and spray performance against the manufacturer's specification.
Common fixes
- Address suspect fuel by refuelling with the vehicle's specified fuel and checking whether symptoms persist.
- Repair the cylinder 6 injector wiring or connector if inspection finds a fault.
- Clean or service the cylinder 6 injector if deposits are confirmed and it is serviceable.
- Replace the cylinder 6 injector if its tested performance is outside the manufacturer's specification.
Can I keep driving?
A steady warning light with a smooth-running engine usually allows a short, gentle trip for diagnosis, but avoid hard acceleration because continued poor combustion can affect emissions and the catalytic converter. Stop if the light flashes, the engine shakes strongly, or power drops enough to make driving unsafe.
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.