Network, generic

U0054 Vehicle Communication Bus C (-) Shorted to Bus C (+)

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Harness crushed so that both Bus C wires touch
Water in a splice or connector bridging the pair
Damaged module input shorting its two bus pins

Symptoms

  • All modules on Bus C unreachable (high-speed type)
  • Engine controller reports CAN fault, connected machine functions fail (Deutz)

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–800
Time1–5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

bus c wiring

Related codes

U0036U0045U0046U0048U0063

References: serdia.deutz.com, serdia.deutz.com, onsemi.com, nxp.com.