Network, generic

U0142 Lost Communication With Body Control Module B

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0142 reports that a second body controller, labelled B, has stopped talking. No maker explains publicly which unit carries this letter; depending on the design it may be a rear body module, a power distribution box or a comfort unit next to the main BCM (U0140) and module A (U0141). The only manufacturer document found that mentions the code is Toyota's 2014 Prius plug-in pre-delivery sheet: the short pin is pulled for shipping to save the battery, so U0142, U0155 and U0100 are expected and simply erased once it is refitted. That makes clear how easily a dormant or unpowered module produces this code. GM's U0100-U02FF logic applies: listeners expect the module's periodic availability message at 9-16 V and log its absence. Invalid data from module B is U0443. Usually no MIL.

Likely causes

Module B without power: fuse, transport short pin or relay missing
Flat battery or battery disconnect leaves a history code
Damaged bus wire or loose connector to module B
Body module B internally faulty

Symptoms

  • Body functions handled by module B do not work
  • Scan tool cannot reach module B
  • Often only a stored code without noticeable fault

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–700
Time0.3–3 h

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

Parts involved

body control modulecan bus wiring

Related codes

U0140U0141U0143U0443

References: static.nhtsa.gov, saabwisonline.com, en.wikipedia.org.