Network, generic

U0154 Lost Communication With Restraints Occupant Classification System Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

U0154 is stored when the occupant classification module goes silent. This unit evaluates sensors in the front passenger seat, such as a weight mat or pressure bladder, and tells the airbag controller whether the seat is empty, holds a child seat or an adult, so that the passenger airbag can be suppressed or allowed. Chrysler is the maker found documenting the code: its restraint controller fault list, submitted to NHTSA in investigation PE11-019, names U0154 as lost communication with the occupant classification module, next to B223D for a fault reported by that module itself. Mercedes-AMG is a special case: on 2023 C- and S-Class models U015400 appears in the AMG drive unit with the engine lamp, put down to Ethernet wake-up timing. Normally the airbag lamp and passenger airbag indicator react. U0455 is invalid data from this module.

Likely causes

Connector under the passenger seat loose, damaged or pulled during seat work
Power or ground of the classification module missing
Classification module or seat sensor internally faulty
Network wake-up timing or software issue (Mercedes-AMG 2023)

Symptoms

  • Airbag warning lamp on
  • Passenger airbag on/off indicator wrong or flashing
  • Passenger airbag deactivated or in a default state

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–1,200
Time0.5–4 h

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

Parts involved

occupant sensing modulecan bus wiring

Related codes

U0151U0152U0153U0455

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