What it means
Ignition C 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 sends Ignition C control signals to the ignition hardware and monitors the electrical state of that control circuit. This code sets when the Ignition C signal is held near ground instead of switching as expected, which can prevent the associated ignition channel from operating correctly.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Rough running or misfire
- Hard starting or no start
- Reduced engine power
How to diagnose it
- Record freeze-frame data and check live misfire or ignition data to see whether the fault is active and when rough running began.
- Inspect the Ignition C control wire and its connectors for chafing, moisture, corrosion, pushed-back pins, or contact with ground.
- With the circuit identified from the vehicle wiring information, check whether the Ignition C signal is being pulled to ground and inspect the harness for a short.
- Wiggle the Ignition C harness and connector while monitoring the signal to see whether movement changes the fault.
- If the wiring and connections are sound, test the Ignition C driver and related ignition component according to the manufacturer's procedure.
Common fixes
- Repair chafed Ignition C wiring that is touching ground.
- Clean or replace corroded Ignition C connector terminals and restore pin fit.
- Repair a damaged connector seal or secure the harness away from rubbing points.
- Replace a confirmed faulty ignition component or control-module driver.
Can I keep driving?
If the engine runs roughly or misfires, avoid hard acceleration and long trips; the affected ignition channel may worsen misfiring and increase emissions. If it stalls or is difficult to start, avoid driving until the fault is diagnosed.
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.