P2E5BCylinder 3 Alternative Fuel Misfire Detected
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2E5B flags misfire on cylinder 3 during operation on CNG or LPG; on petrol the matching code is P0303. No manufacturer publishes P2E5B. One cause that belongs to gas engines in particular is valve seat wear: dry gaseous fuels leave few combustion products, so valve and seat insert rub metal on metal and the seat recedes, as a Honda patent on seat materials explains. Once a valve stops sealing, compression in that cylinder falls and combustion becomes unreliable. For this reason natural-gas engines usually carry hardened exhaust valves and seats, and Ford's 2014 F-150 gaseous-fuel prep package added hardened valves, seats, pistons and rings. A compression or leak-down test on cylinder 3 separates this from injector or ignition faults; engines converted without hardened parts deserve extra suspicion.
- What you may notice
- Misfire on gas that slowly gets worse, later also on petrol
- Low compression on cylinder 3, sometimes a ticking valve noise
- Check engine light
- Likely causes
- LikelyFaulty gas injector on cylinder 3
- PossibleValve seat recession on cylinder 3 from dry gas operation, valve no longer seals
- PossibleWorn plug or failing coil on cylinder 3
- RareRetrofit gas conversion on an engine without hardened valves and seats
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.