U302C code meaning
Ignition Output Off/On/Start
What U302C means
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.
U302C at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U302C
- 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
Common causes of U302C
- 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
- Less likelyFaulty output stage in the sending module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ignition outputOutput wiring
What each part of U302C means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 2C | The exact fault in that area. |
What to do next
- Note U302C and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U302C
What does U302C mean?
U302C means "Ignition Output Off/On/Start". 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 a generic code, so it means the same on every make.
Is it safe to drive with U302C?
U302C does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U302C fail an emissions test?
U302C is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U302C to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U302C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.