Body, generic

B0057 Third Row Center Seat Belt Sensor

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

In J2012, B0057 is the buckle sensor for the third row's centre seat, a position found only in eight-seat vans and SUVs. FMVSS 208 S7.5(c) will require a belt warning there from September 2028. No carmaker documents B0057 publicly with this meaning. Older GM airbag modules give the number a different job: the 2006 Saab 9-5 and the Saab 9-3 store B0057 when the passenger pretensioner loop resistance stays under 1.5 ± 0.2 ohms for 2 seconds. GM bulletin 14609 lists B0057 with B0058, B0059 and B0064 to B0066 on 2004-09 Colorado and Canyon extended cabs, whose rear door harness can suffer fatigue breaks and can disable the front pretensioners; GM extended coverage to 10 years. On older GM vehicles, check the pretensioner loop first.

Likely causes

Faulty buckle sensor or lead at the middle third-row seat
Older GM trucks: broken wire in the rear door harness to the pretensioner (bulletin 14609)
Older GM/Saab module: shorted passenger pretensioner squib or connector

Symptoms

  • Airbag warning lamp on
  • Depending on the module: wrong belt status for the middle third-row seat, or passenger pretensioner possibly inactive
  • Safety note: buckle and pretensioner plugs carry firing circuits nearby; only unplug them with the battery disconnected and the wait time observed

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€60–600
Time0.5–3 h

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

Parts involved

seat belt buckle switchsrs seat wiringpassenger seatbelt pretensionersrs control module

Related codes

B0056B0058B0077B0064

References: law.cornell.edu, saabwisonline.com, saabwisonline.com, static.nhtsa.gov.