P2E5D: Cylinder 5 Alternative Fuel Misfire Detected

What it means

Misfire detected on cylinder 5 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

The controller detects incomplete combustion by tracking crankshaft speed while the engine operates on alternative fuel. P2E5D singles out cylinder 5, so diagnosis should establish whether its alternative-fuel injector or electrical connection is failing while the other cylinders continue to run normally.

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. Check scan-tool misfire counts and freeze-frame data to confirm cylinder 5 involvement and the fuel mode at the time of the fault.
2. Compare how the engine runs on alternative fuel and petrol, noting whether cylinder 5's misfire occurs in both modes.
3. Inspect cylinder 5's alternative-fuel injector connector and wiring for damage, corrosion, poor fit, or leakage.
4. Check the alternative-fuel quality and supply, particularly if the fault appeared after refuelling or during acceleration.
5. Test cylinder 5's alternative-fuel injector and compare its operation with other cylinders and the manufacturer's specification.
6. If the misfire is present on petrol as well, inspect cylinder 5 ignition and mechanical condition.

Common fixes

• Repair a loose or damaged cylinder 5 injector connector or harness.
• Replace suspect fuel with known-good alternative fuel if contamination or poor quality is plausible.
• Clean or replace the cylinder 5 alternative-fuel injector after confirming weak or restricted flow.
• Repair a confirmed pressure regulation or alternative-fuel supply fault.

Can I keep driving?

Avoid high engine loads and stop if the check-engine light flashes or the engine runs very roughly, as unburned fuel can damage the catalytic converter. If the engine is smooth on petrol, switch to petrol if possible and arrange diagnosis soon.