Worn or fouled spark plug specific to cylinder 2, often due to alternative fuel deposits; Faulty ignition coil or plug wire on cylinder 2 that breaks down under alternative fuel load; Leaking or clogged alternative fuel injector on cylinder 2, causing an incorrect air-fuel mixture; Vacuum leak near cylinder 2 intake runner that leans out the mixture only on the alternative fuel map; Low compression on cylinder 2 from worn rings, valves, or a head gasket issue; Contaminated alternative fuel or a fuel pressure problem affecting the entire rail but most noticeable on one cylinder; Engine control module software or calibration issue that misinterprets crankshaft signals during alternative fuel operation

DTC codes / P2Exx · Hybrid propulsion / P2E5A

P2E5ACylinder 2 Alternative Fuel Misfire Detected

Q: What does code P2E5A mean?

Cylinder 2 Alternative Fuel Misfire Detected. P2E5A indicates that the engine control module has detected a misfire on cylinder 2 while the engine is running on an alternative fuel such as compressed natural gas, propane, or E85. The computer monitors crankshaft speed fluctuations and identifies that cylinder 2 is not contributing power evenly, which can damage the catalytic converter if ignored.

P2E5A indicates that the engine control module has detected a misfire on cylinder 2 while the engine is running on an alternative fuel such as compressed natural gas, propane, or E85. The computer monitors crankshaft speed fluctuations and identifies that cylinder 2 is not contributing power evenly, which can damage the catalytic converter if ignored.

SystemPowertrain

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illuminated check engine light, often flashing if the misfire is severe
Rough idle or shaking that is more noticeable when the engine is cold or under light load
Hesitation or stumble during acceleration, especially when switching to alternative fuel
Reduced fuel economy and a noticeable loss of power
Often no symptoms besides the warning light when the misfire is intermittent
A sulfur or rotten egg smell from the exhaust if unburned fuel reaches the catalytic converter

Common causes, most likely first

Worn or fouled spark plug specific to cylinder 2, often due to alternative fuel deposits
Faulty ignition coil or plug wire on cylinder 2 that breaks down under alternative fuel load
Leaking or clogged alternative fuel injector on cylinder 2, causing an incorrect air-fuel mixture
Vacuum leak near cylinder 2 intake runner that leans out the mixture only on the alternative fuel map
Low compression on cylinder 2 from worn rings, valves, or a head gasket issue
Contaminated alternative fuel or a fuel pressure problem affecting the entire rail but most noticeable on one cylinder
Engine control module software or calibration issue that misinterprets crankshaft signals during alternative fuel operation

How to diagnose and fix it

Scan all stored and pending codes, then check freeze-frame data for engine speed, load, and fuel trims when the misfire was set
Perform a cylinder balance test or misfire counter check with a scan tool to confirm cylinder 2 is the only affected cylinder
Inspect the spark plug, ignition coil, and plug wire on cylinder 2, replacing any component that shows wear, carbon tracking, or incorrect gap
Check for vacuum leaks at the intake manifold and around cylinder 2 using a smoke machine or propane enrichment test
Measure fuel trim and injector pulse width on cylinder 2 compared to other cylinders, then test the alternative fuel injector for flow and spray pattern
Run a compression test and, if low, a cylinder leak-down test to rule out mechanical faults before replacing ignition or fuel parts
After repairs, clear codes and drive the vehicle under the same conditions that originally set the code to verify the misfire is gone

Alternative fuel misfires that fool technicians

Alternative fuels such as E85 and propane burn cooler and can foul spark plugs differently than gasoline, so a plug that looks fine may still misfire under alternative fuel operation.
A misfire code for only one cylinder on an alternative fuel vehicle often traces to a single injector or coil, but a vacuum leak at the intake runner for that cylinder can mimic the same symptom.
The engine control module may set P2E5A only when the vehicle is running on the alternative fuel map, so a misfire that disappears on gasoline can still be a real ignition or fuel delivery fault.
Technicians sometimes replace all coils or plugs when only cylinder 2 is affected, but the misfire counter and freeze-frame data usually point to the exact cylinder and operating condition.
A flashing check engine light with this code means the misfire is severe enough to damage the catalytic converter, so diagnosis should not be delayed even if the vehicle seems to run acceptably.

Can I keep driving with P2E5A?

If the check engine light is flashing, stop driving as soon as it is safe because raw fuel is entering the exhaust and can destroy the catalytic converter. With a steady light and mild symptoms, keep driving to a minimum and avoid heavy acceleration or towing until the misfire is repaired.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.