Network, generic

U0057 Vehicle Communication Bus D (+) Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0057 indicates an interrupted (+) wire on Vehicle Communication Bus D. Where Bus D is a two-wire CAN, such as the private chassis CAN Bentley files under that name, it is CAN-High. Apart from splitting the bus, a break changes the line itself: Texas Instruments describes high-speed CAN as a 120-ohm twisted pair terminated at both far ends, and warns against placing a terminator inside a node because the line loses it when that node is unplugged. A break that cuts one terminator off leaves part of the wire unterminated, so reflections can distort edges for the remaining nodes. The transceiver cannot detect the interruption itself (NXP). No manufacturer documents U0057 publicly. Look for connectors left open after repairs and conductors fractured where the harness flexes.

Likely causes

(+) wire of Bus D broken where the harness flexes
Connector left unplugged or not latched after a repair
Backed-out or spread terminal

Symptoms

  • Modules beyond the break unreachable
  • Sporadic errors among the remaining modules

Repair estimate

DifficultyHardWorkshop job
Parts and labour€60–700
Time0.5–5 h

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

Parts involved

bus d wiringmodule connector

Related codes

U0039U0048U0055U0058U0060

References: ti.com, nxp.com, static.nhtsa.gov.