U0083Vehicle Communication Bus F (+) Low
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U0083 means the (+) line of Vehicle Communication Bus F is held too low, normally by a short to ground. On FlexRay, which Audi links to Bus F, the line is bus plus (BP). NXP builds its TJA1081B to survive such a short and lists short-circuit detection on the bus lines among its diagnostic features; with BP at ground instead of its idle level of roughly half the 5 V supply, the difference to BM no longer swings the way the receivers expect. If Bus F is a CAN, a grounded CAN-High stops dominant bits, which onsemi found blocks the bus. Among Volvo's typical triggers for the truck code U008088 is CAN-High grounded. No manufacturer documents U0083 itself. With the battery disconnected, measure the (+) wire to chassis.
- What you may notice
- Several functions on Bus F fail at once
- Many lost-communication codes in other modules
- Likely causes
- Likely(+) wire of Bus F chafed through to body metal
- PossibleHarness pinched by a trim panel or bracket
- RareFaulty transceiver pulling the (+) line 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.