What it means
Ignition I control signal stuck low — short to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The PCM uses the ignition I control signal to trigger the corresponding ignition coil group. This code sets when that control signal is held lower than expected, commonly because the circuit is shorted to ground or has a connection fault.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 I circuit goes low and how the engine responds.
- Inspect the ignition I wiring and connectors for chafing, moisture, corrosion, or terminals pushed back into the connector.
- With the circuit active, gently move accessible sections of the harness while monitoring live data for a change that could reveal a contact fault.
- Use the wiring diagram to test the ignition I control wire for a short to ground and check its continuity as directed by the manufacturer's procedure.
- If the wiring is sound, test the ignition I coil group and PCM control output using the manufacturer's diagnostic procedure.
Common fixes
- Repair chafed ignition I wiring that is shorting to ground.
- Clean or repair corroded connectors and restore pushed-back terminals.
- Repair a confirmed fault in the ignition I coil group.
- Repair the PCM only if its control output is confirmed faulty.
Can I keep driving?
The low control signal can leave the ignition I coil group unable to fire correctly, causing misfires, poor running, or a no-start. Avoid hard acceleration and stop driving if the engine misfires severely 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.