P22E7: Cylinder 4 Alternative Fuel Injector Control Circuit High

What it means

The cylinder 4 alternative-fuel injector control circuit has a voltage above the expected range. This indicates an electrical circuit fault, not necessarily an injector flow problem or short to battery.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

A bi-fuel vehicle uses a dedicated alternative-fuel injector for cylinder 4, driven by a circuit distinct from the petrol or diesel injection system. This code means the control module sees cylinder 4 injector-circuit voltage above its expected range; the reading indicates an electrical problem but does not alone establish a short to battery.

Common causes

Most likely first.

1. Short to B+
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Check engine light on
• Misfire or rough idle on the affected cylinder
• Increased fuel consumption
• Possible fuel smell or smoke from exhaust

How to diagnose it

1. Use freeze-frame data and live misfire counts to confirm whether the high reading occurs during alternative-fuel operation and affects cylinder 4.
2. Inspect the cylinder 4 injector connector and harness for damaged insulation, pinched wiring, corrosion, or a terminal touching a power source.
3. With the circuit isolated as directed by the manufacturer, check the cylinder 4 control wire for an unintended connection to battery voltage.
4. Measure the circuit at the injector connector and control-module connector, comparing voltage and continuity with the manufacturer's specification to pinpoint where the high voltage enters.
5. If the wiring and connectors pass, test the cylinder 4 injector and module driver according to the manufacturer's procedure.

Common fixes

• Secure or replace a cylinder 4 connector terminal that is loose, corroded, or contacting another circuit.
• Repair pinched or damaged wiring that is allowing battery voltage onto the injector control circuit.
• Replace the cylinder 4 alternative-fuel injector if it fails electrical testing.
• Repair or replace the control module if testing confirms a faulty cylinder 4 driver.

Can I keep driving?

Do not use the alternative-fuel mode while cylinder 4 runs roughly; use another fuel mode only if the vehicle is smooth and the manufacturer permits it. A persistent misfire can increase emissions and damage the catalytic converter, and fuel odour or smoke calls for stopping the vehicle.