Body, generic

B0050 Driver Seat Belt Sensor

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0050 monitors the switch in the driver's belt buckle that tells the restraint module whether the belt is latched; the module uses it for the belt reminder and for choosing the airbag and pretensioner response. Usually a two-wire Hall sensor whose current changes when the steel tongue enters the buckle. FCA documents B0050 with this wording: its 2016-17 parts notes for the Dart, Cherokee and Chrysler 200 list B0050-13 as an open circuit of the driver belt sensor, and TSB 10-001-23 for the 2015-22 Renegade and Fiat 500X lists B0050-13 and B0050-1D (out of range), traced to terminal corrosion at the inline buckle connector under the seat. Mitsubishi uses B0052 for the passenger buckle. The airbag lamp lights.

Likely causes

Corroded terminals at the inline connector between buckle and seat harness
Faulty Hall sensor or switch inside the driver buckle
Buckle lead pinched or stretched by the seat track
Foreign object or debris in the buckle confusing the sensor

Symptoms

  • Airbag warning lamp on
  • Belt reminder for the driver may warn wrongly or stay silent
  • Restraint module may treat the driver as unbelted and adapt airbag and pretensioner firing
  • Safety note: the buckle connector sits under the seat next to the side airbag and pretensioner plugs; disconnect the battery and observe the wait time before unplugging anything

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–450
Time0.5–2 h

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

Parts involved

seat belt buckle switchsrs seat wiringseat harness connectorsrs control module

Related codes

B0051B0052B0070

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, mitsubishitechinfo.com.