U007AControl Module Communication Bus H Off
- Generic OBD-II code · Network
- How the car detects it
- Bus H appears in no public manufacturer document for U007A; the code merely says that one module's CAN controller has switched to bus off on the network its maker labels H. A sensible check order follows from the physics. A high-speed CAN carries a 120 ohm resistor at each end, so with the battery disconnected the two wires should show roughly 60 ohms between them; about 120 ohms points to a missing terminator, near zero to the wires touching. With ignition on, a dominant bit pulls CAN-High toward 3.5 V and CAN-Low toward 1.5 V. As onsemi shows, a bus that is held recessive pushes a sender into bus off within a few dozen bit times, so shorts and transceiver damage come before software in the search.
- What you may notice
- Functions on Bus H fail or work only intermittently
- Warning messages from several systems
- Likely causes
- PossibleBus H wires shorted together
- PossibleTerminating resistor open or a terminating module disconnected
- RareTransceiver damaged, e.g. by overvoltage
- 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.