Body, generic

B0051 First Row Center Seat Belt Sensor

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0051 belongs to the buckle sensor of a middle seat in the front row, found in pickups and vans with a front bench for three. FMVSS 208 requires a belt warning only for the outboard front seats, so a centre buckle sensor is extra equipment that feeds the restraint module and, where fitted, a reminder for that place. Typical hardware is a non-contacting Hall buckle switch as offered by CTS and described by Allegro. No carmaker documents B0051 with this meaning; Mitsubishi uses the same J2012 pattern for the passenger buckle, B0052, with an open or invalid signal for 2 seconds. Older GM modules (Saab 9-5 2006, 9-3) store B0051 as Deployment Commanded, a crash record. Airbag lamp on.

Likely causes

Loose or corroded connector of the centre buckle under the bench seat
Faulty Hall switch in the centre buckle
Lead strained by a fold-down centre seat or console

Symptoms

  • Airbag warning lamp on
  • Centre seat belt reminder may be wrong or missing
  • 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 wiringsrs control module

Related codes

B0050B0052B0071

References: law.cornell.edu, ctscorp.com, allegromicro.com, mitsubishitechinfo.com.