U302FIgnition Output Accessory
- Generic OBD-II code · Network
- How the car detects it
- U302F is logged by the module that switches the accessory feed for audio, sockets or windows when that feed is out of step with its own command. Two normal behaviours have to be ruled out first. Keyless systems cut accessory power during cranking: in Tokai Rika's patent US7254466B2 the power supply unit releases the accessory relay when start is requested and re-energizes it only once the engine controller reports that combustion has begun. GM's 2012 pickups, on the other hand, keep accessory voltage on after key-off through a relay inside the BCM for roughly 10 minutes, unless a door is opened. Outside those windows, a live feed in a locked car suggests a welded relay or a driver stuck on, and a dead feed in accessory an open relay, fuse or wire. No manufacturer documents U302F publicly.
- What you may notice
- Radio, sockets or windows dead in accessory mode
- Accessories still on long after locking, battery drained
- Likely causes
- PossibleAccessory relay welded or its driver stuck on
- PossibleAccessory relay not pulling in
- PossibleBlown accessory fuse or open feed wire
- RareRetrofitted equipment overloading or backfeeding the accessory feed
- Repair
- Easy · Often possible to do yourself.Typical cost: €10 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.