U0054Vehicle Communication Bus C (-) Shorted to Bus C (+)
- Generic OBD-II code · Network
- Can trigger limp mode
- How the car detects it
- U0054 describes a short between the two wires of Vehicle Communication Bus C. Deutz uses it in main and secondary EMR L1 engine controllers as a short circuit on CAN 4, the same channel whose open circuit is U0048. On a high-speed CAN the bridged pair carries no differential voltage, so no dominant bit can form; onsemi measured the node's draw falling to about 47 mA, the lowest of all short types, because almost no transmission takes place. NXP's TJA1041 note adds that bus diagnosis in the transceiver cannot recognise this case. On fault-tolerant low-speed hardware like NXP's TJA1055, the bridged pair first looks like an endless dominant state; after 0.3 to 1.6 ms the chip disables CAN-Low and continues on one wire. Resistance across the pair close to zero, measured without battery, confirms it.
- What you may notice
- All modules on Bus C unreachable (high-speed type)
- Engine controller reports CAN fault, connected machine functions fail (Deutz)
- Likely causes
- LikelyHarness crushed so that both Bus C wires touch
- PossibleWater in a splice or connector bridging the pair
- RareDamaged module input shorting its two bus pins
- 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.