U0032
Vehicle Communication Bus A (+) High
The communication bus A high-side line (CAN-H or equivalent) is at a higher voltage than allowed. Likely short to power or a transceiver fault that pulls the line high.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: hard
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
Ordered by how often each turns out to be the cause.
- Bus high line shorted to batteryCommon
- Transceiver in one node failedPossible
- Gateway module routing CAN messages incorrectlyLess likely
Parts involved
- Bus A Wiring
- Bus A Transceiver
U0032 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.