What it means
Fault on the combined ACC/OFF ignition output. A communication loss with this module breaks any function relying on its data — diagnostic tools may show 'no response' and dependent modules can fall into limp mode.
At a glance
- Usually lights the warning light of the system that lost communication
How it works
The combined ACC/OFF ignition output supports accessory-mode operation and reports the transition to the off state. The control module monitors this combined output; this code sets when the ACC/OFF signal or its reported state is faulty or unavailable.
Common causes
Most likely first.
- Wiring or relay fault
- Gateway module routing CAN messages incorrectly
- CAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
How to diagnose it
- Scan all modules and note whether the fault affects accessory operation, shutdown, or both.
- Use freeze-frame and live data to compare the reported ACC/OFF output status with the selected ignition state.
- Inspect the combined output's wiring, connectors, fuse, and relay for damage, corrosion, or a poor connection.
- Check the output in both accessory and off states, comparing measurements with the manufacturer's specification.
- If the circuit is sound, check gateway routing and CAN termination for communication faults.
Common fixes
- Clean and secure a loose or corroded ACC/OFF connection.
- Replace a faulty relay or fuse after finding the reason it failed.
- Repair damaged wiring in the combined output circuit.
- Correct a confirmed gateway routing or CAN termination issue.
Can I keep driving?
If the vehicle starts and drives normally, limit driving to what is needed for diagnosis. The combined output fault can disable accessories or prevent proper shutdown, so watch for affected visibility or safety features and battery drain.
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.