Network, generic

U0055 Vehicle Communication Bus D

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U0055 covers Vehicle Communication Bus D as a whole, the fourth network slot a manufacturer can assign freely. Volvo documents it for the 2016-17 XC90 T8 plug-in hybrid: the engine control module stores U005500 with fault type intermittent, the driver information display shows the turtle symbol and the car lacks power. Volvo classifies it as a software fault, tells technicians not to replace parts, and announced new software for week 16 of 2017, until then the code was simply cleared. Bentley assigns Bus D to a private chassis CAN and documents its performance code U0056. Without such a bulletin, look first for lost-communication codes that show which module on Bus D is missing, then check its supply, ground and connectors.

Likely causes

Control module software misjudging Bus D (Volvo XC90 T8: ECM update)
Supply or ground fault at a module on Bus D
Damaged wiring or loose connector on Bus D

Symptoms

  • Turtle symbol and reduced engine power (Volvo XC90 T8)
  • Functions of modules on Bus D unavailable
  • Lost-communication codes stored alongside

Repair estimate

DifficultyHardWorkshop job
Parts and labour€50–900
Time0.5–5 h

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

Parts involved

bus d wiringbus d nodes

Related codes

U0028U0037U0046U0056U0064

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.