U007A code meaning
Control Module Communication Bus H Off
What U007A means
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.
U007A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyHard
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U007A
- Functions on Bus H fail or work only intermittently
- Warning messages from several systems
Common causes of U007A
- PossibleBus H wires shorted together
- PossibleTerminating resistor open or a terminating module disconnected
- Less likelyTransceiver damaged, e.g. by overvoltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bus h wiringCAN transceiver
What each part of U007A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7A | The exact fault in that area. |
What to do next
- Note U007A 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 U007A
What does U007A mean?
U007A means "Control Module Communication Bus H Off". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with U007A?
U007A does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U007A fail an emissions test?
U007A 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 U007A to fix?
Difficulty: hard. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will U007A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.