What it means
The drive circuit for the cylinder 4 alternative-fuel injector is open. Bi-fuel vehicles have a second set of injectors for CNG, LPG, or hydrogen — separate from the petrol/diesel injectors.
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 has a dedicated alternative-fuel injector for cylinder 4, separate from the petrol or diesel injector. The control module monitors the cylinder 4 injector drive circuit and sets this code when it detects an open path that prevents the injector from being driven as expected.
Common causes
Most likely first.
- Injector winding open
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
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
- Check freeze-frame data and misfire counts to confirm the fault occurs while the alternative-fuel system is operating and is isolated to cylinder 4.
- Inspect the cylinder 4 alternative-fuel injector connector for a pushed-back pin, poor fit, corrosion, or damage, and check its wiring for breaks or strain.
- With the ignition off and the circuit isolated as specified by the manufacturer, check the cylinder 4 injector winding for continuity and compare it with the manufacturer's specification.
- Check continuity through the injector control wiring and its connections to the control module, looking for an open circuit or an intermittent break while gently moving the harness.
- If the injector and wiring pass, have the control-module connector and driver circuit checked for an internal open or cracked solder joint using the manufacturer's diagnostic procedure.
Common fixes
- Reconnect and secure a loose cylinder 4 injector connector or repair a pushed-back terminal.
- Repair an open or damaged section of cylinder 4 injector wiring.
- Replace the cylinder 4 alternative-fuel injector if its winding is open.
- Repair or replace the control module if testing confirms an internal driver fault.
Can I keep driving?
Avoid running the vehicle on the alternative fuel while cylinder 4 is misfiring; use the other fuel mode only if the vehicle operates smoothly and the manufacturer permits it. Continued misfire can increase emissions and damage the catalytic converter; stop if you smell fuel or see smoke.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.