Body, generic

B0070 Driver Seat Belt Pretensioner A Deployment Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0070 covers the firing loop of the driver's first (A) belt pretensioner, the squib the airbag module ignites to take slack out of the belt in a crash. A short or open in that loop lets the module no longer count on the device, so it lights the airbag lamp. Toyota names the code in exactly this sense: its Tundra bulletin T-SB-0057-22 (model year 2022) lists B007011 (short to ground) and B007012 (short to battery), there triggered by the wireless Qi charger and cured by reprogramming the SRS ECU. J2012 does not fix which device is A; GM notes that a front seat may carry a retractor, buckle or anchor pretensioner, or more than one. Mitsubishi logs its front retractor units under its own codes B1029/B102A. Saab 9-3 airbag modules use B0070 for the passenger curtain loop instead.

Likely causes

Loose or corroded plug at the driver pretensioner (B-pillar base or seat side)
Firing lead chafed by seat rails or trim clips
Interference from added electronics, e.g. a wireless charger (Toyota Tundra 2022, ECU update)
Internal fault in the pretensioner squib

Symptoms

  • Airbag warning lamp on
  • Driver belt is not tightened in a crash; airbags themselves are usually unaffected
  • Safety note: the pretensioner is a pyrotechnic part; work on it only with the battery disconnected and the wait time observed, ideally at a specialist workshop

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–700
Time0.5–2.5 h

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

Parts involved

driver seatbelt pretensionersquib circuitsrs control module

Related codes

B0079B007EB0072B0050

References: static.nhtsa.gov, gmstc.com, mitsubishitechinfo.com, crashstats.nhtsa.dot.gov.