P2E5F: Cylinder 7 Alternative Fuel Misfire Detected

What it means

Misfire detected on cylinder 7 during alternative fuel operation. Specific to bi-fuel CNG/LPG operation.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test
• The engine or gearbox may go into limp mode

How it works

When the engine runs on alternative fuel, the controller detects misfires by monitoring crankshaft speed. P2E5F identifies cylinder 7, directing checks toward that cylinder's alternative-fuel injector and connection rather than treating the fault as a general engine misfire.

Common causes

Most likely first.

1. Injector clogged or weak
2. Fuel quality off-spec

Symptoms

• Check engine light on or flashing
• Rough idle and uneven running
• Power loss, hesitation under acceleration
• Increased fuel consumption
• Possible smell of unburned fuel from exhaust

How to diagnose it

1. Read cylinder-specific misfire counts and freeze-frame data to verify that cylinder 7 misfired in alternative-fuel mode.
2. Compare operation on alternative fuel with petrol and note whether cylinder 7 runs normally on petrol.
3. Inspect the cylinder 7 alternative-fuel injector connector and wiring for loose connections, corrosion, damage, or leakage.
4. Check alternative-fuel quality and supply conditions, particularly if the issue began after refuelling or shows up under load.
5. Test cylinder 7's alternative-fuel injector operation and delivery against the other cylinders and the manufacturer's specification.
6. If cylinder 7 also misfires on petrol, check its ignition and mechanical condition.

Common fixes

• Repair loose, corroded, or damaged wiring at the cylinder 7 injector.
• Use known-good alternative fuel if the current fuel quality is suspect.
• Clean or replace the cylinder 7 alternative-fuel injector if a restriction or weak output is confirmed.
• Correct a confirmed fault in the alternative-fuel supply or pressure regulation.

Can I keep driving?

Avoid hard acceleration, and stop if the check-engine light flashes or the engine runs very roughly because misfire can damage the catalytic converter. If the engine runs smoothly on petrol, switch modes if available and arrange diagnosis soon.