Network, generic

U0072 Vehicle Communication Bus E (-) Shorted to Bus E (+)

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U0072 describes the (-) and (+) wires of Vehicle Communication Bus E touching each other. On a high-speed CAN this ends communication: with the pair bridged there is no differential voltage, onsemi found transmission impossible, and NXP's TJA1041 note lists the short with the faults its bus diagnosis cannot detect. A fault-tolerant low-speed CAN degrades more gently. NXP's TJA1055 treats the short as a dominant level that never ends, confirms it in 0.3-1.6 ms, shuts down its CAN-Low driver and falls back to working over one wire, and returns to differential mode once the short is gone and the recessive state holds for a while. No manufacturer documents U0072 publicly. Separating connectors along the bus while measuring the resistance between the wires narrows the location down.

Likely causes

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

Symptoms

  • All modules on Bus E unreachable (high-speed type)
  • Several warning messages, gateway reports lost communication

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 e wiring

Related codes

U0036U0045U0054U0063U0064

References: onsemi.com, nxp.com, nxp.com.