What it means
The ignition J control signal circuit is open — typically the PCM drive line for the first ignition coil group has lost continuity.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The PCM sends an ignition J control signal to the corresponding ignition coil group to produce spark. This code sets when the control circuit is open and the expected electrical path is missing.
Common causes
Most likely first.
- Open wire between PCM and coil
- Pin pushed back out of connector body
- Cracked solder joint inside the module or sensor
Symptoms
- Check engine light on
- Hard starting or no-start
- Engine may misfire or run roughly
- Reduced engine performance
How to diagnose it
- Check freeze-frame data and ignition or misfire live data to see when the ignition J circuit fault occurs and which operating conditions are affected.
- Inspect the ignition J coil-group connector and the wiring between that group and the PCM for breaks, loose connections, corrosion, or pushed-back pins.
- Use the wiring diagram to check continuity of the ignition J control wire with the circuit safely isolated as directed by the manufacturer's procedure.
- Check the coil-group supply and ground, where applicable, to distinguish an open control wire from a separate power or ground issue.
- If the wiring and connectors pass, test the ignition J coil group and PCM output using the manufacturer's diagnostic procedure.
Common fixes
- Reconnect and secure the ignition J control connector.
- Repair an open wire or pushed-back terminal in the ignition J control circuit.
- Repair a confirmed fault in the ignition J coil group.
- Repair the PCM only if its control output is confirmed faulty.
Can I keep driving?
A failed ignition J control signal can cause misfiring, poor performance, or a no-start. Avoid hard acceleration, and stop driving if the engine runs severely unevenly or stalls.
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.