P2E58: Alternative Fuel Random/Multiple Cylinder Misfire Detected

What it means

Random or multiple cylinder misfire detected during alternative fuel operation. System-wide fueling or ignition issue.

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 engine controller tracks crankshaft speed changes to detect weak or missing combustion while the engine runs on its alternative fuel system, such as CNG or LPG. This code sets when misfires occur across multiple cylinders or cannot be isolated to one cylinder during alternative-fuel operation.

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. Use a scan tool to review freeze-frame data, misfire counts by cylinder, and whether the event occurred on alternative fuel or petrol.
2. Check whether the engine runs smoothly on petrol; a fault limited to alternative-fuel operation points toward that fuel system.
3. Inspect the alternative-fuel supply, injector wiring and connectors for damage, loose connections, leaks, or contamination.
4. Check the alternative-fuel tank contents and fuel quality, especially if the problem began after refuelling.
5. Test alternative-fuel pressure regulation and injector operation under the conditions recorded in the freeze frame, comparing results with the manufacturer's specification.
6. If misfires also occur on petrol, check the affected cylinders' ignition and mechanical condition before replacing alternative-fuel parts.

Common fixes

• Refill with known-good alternative fuel if the tank contents are low or suspect.
• Repair loose, damaged, or corroded alternative-fuel injector wiring and connectors.
• Clean or replace a restricted alternative-fuel injector after confirming its fault.
• Repair the alternative-fuel pressure regulator or supply fault if testing confirms unstable delivery.

Can I keep driving?

Avoid hard acceleration and stop driving if the check-engine light flashes or the engine runs very roughly; unburned fuel can overheat and damage the catalytic converter. If it runs smoothly on petrol, switch to petrol if the vehicle permits and arrange diagnosis soon.