U008CVehicle Communication Bus G (+) Low
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U008C indicates a (+) wire on Vehicle Communication Bus G pulled too low, usually grounded. No manufacturer documents U008C publicly. On a high-speed CAN the (+) wire is CAN-High, which Texas Instruments describes as rising from about 2.5 V to 3.5 V for every dominant bit while CAN-Low drops to 1.5 V, giving the 2 V difference receivers decode. A grounded CAN-High cannot rise, so no node can assert a dominant bit; onsemi saw transmission fail outright in this state. Each failed frame raises the sender's error counter, so the same module may also log U0079 once it goes bus off. The whole network falls silent and other networks log the missing modules. With the battery disconnected, CAN-High showing only a few ohms to chassis confirms the short.
- What you may notice
- All modules on Bus G drop out together
- Many warnings and lost-communication codes at once
- Likely causes
- Likely(+) wire of Bus G chafed against body metal
- PossibleHarness pinched by a screw, panel or seat
- RareDefective transceiver holding CAN-High to ground
- Repair
- Hard · Usually a job for a workshop.Typical cost: €60 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.