U302CIgnition Output Off/On/Start
- Generic OBD-II code · Network
- How the car detects it
- U302C covers an ignition output that encodes several states on one wire: Off, On and Start each get their own level, so a single conductor passes the power mode on to other units. It is the sending counterpart of coded inputs like the Off/Run/Crank circuit that GM's wiring manual for its 2012 light-duty trucks shows between ignition switch and body controller, which uses separate levels for key removed, key in at off, running and cranking. A module producing such a coded line stores U302C once the level read back at its own pin differs from the state it means to transmit. No manufacturer documents U302C publicly. Since receivers evaluate voltage bands rather than on or off, a partial short, an extra load or a corroded pin can turn run into start or off without the line going dead, so measure it in each mode with receivers connected.
- What you may notice
- Other modules acting on a wrong power mode, e.g. shutting down or not waking
- Sporadic warnings that change with key position or button presses
- Likely causes
- PossibleCorroded or loose pin shifting the coded level
- PossibleFaulty input in a receiving module pulling the line out of its band
- PossibleChafed wire with a partial short to ground or voltage
- RareFaulty output stage in the sending module
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.