P2E61: Alternative Fuel Misfire Detected With Low Fuel

What it means

Misfire detected during alternative fuel operation with low tank level. Possible fuel starvation or pressure regulation off.

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 detects misfires while the engine is using alternative fuel and records that the tank level is low. A low supply can interrupt fuel delivery, and pressure regulation may become unstable as the tank empties, causing combustion to falter.

Common causes

Most likely first.

1. Alt fuel tank near empty
2. Pressure regulation unstable at low level

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. Review freeze-frame data, alternative-fuel level, and misfire counts to confirm that the fault occurred with a low tank reading.
2. Refill with the correct alternative fuel from a reliable source, then check whether the misfire returns with an adequate supply.
3. Compare operation on alternative fuel and petrol to see whether the issue is limited to alternative-fuel delivery.
4. Inspect the alternative-fuel supply lines, electrical connections, and pressure regulator for damage, looseness, or leakage.
5. Monitor alternative-fuel pressure and delivery as the system operates, comparing results with the manufacturer's specification.
6. If misfires persist after refuelling, check injector operation and investigate whether the tank-level reading or supply system is inaccurate.

Common fixes

• Refill the alternative-fuel tank before continuing to operate in that mode.
• Repair a loose or damaged connection in the alternative-fuel supply or regulator circuit.
• Repair or replace a confirmed faulty pressure regulator or supply component.
• Clean or replace an injector only if testing confirms that it is restricted or weak.

Can I keep driving?

Avoid relying on alternative-fuel operation until the tank is refilled and the misfire is checked; loss of power can make merging or passing unsafe. Stop driving if the check-engine light flashes or the engine runs roughly, since continued misfire can damage the catalytic converter.