Network, generic

U0046 Vehicle Communication Bus C

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U0046 covers Vehicle Communication Bus C in general, the third manufacturer-assigned network slot after Bus A and Bus B. Public uses are rare. Stellantis lists U0046-00 among the faults addressed by powertrain control module flash 18-071-26 for the 2025 Ram 1500 with the 3.0-litre Hurricane twin-turbo six; the bulletin pairs its long code list with a possible MIL but does not single out the bus fault as the reason for the lamp. Ford's 2014 Boss 302S code table names U0046 as well, without marking it as a MIL code. Behind the code there may be a wiring fault, a module that stops talking or plain software, so check for accompanying lost-communication codes first, then supply, ground and bus wiring of the modules on that network before replacing parts.

Likely causes

Control module software that misjudges the bus (Ram 1500: PCM flash)
Damaged bus wiring or poorly seated connector on Bus C
Supply or ground fault at a module on Bus C

Symptoms

  • Check-engine lamp possible together with other stored codes (Ram 1500)
  • Functions of modules on Bus C 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 c wiringbus c nodes

Related codes

U0028U0037U0047U0048U0055

References: static.nhtsa.gov, performanceparts.ford.com, law.cornell.edu.