Body, generic

B0090 Left Frontal Restraints Sensor

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0090 concerns the left frontal crash sensor, a satellite accelerometer in the front crumple zone that tells the airbag module early how hard the front end is being hit. Bosch notes such upfront units sharpen frontal crash detection beside the central sensors. Several makers use the code exactly so. Acura bulletin 18-016 (2017 ILX) describes B0090-87, a missing signal of the left frontal impact sensor, caused by water entering the connector through a wire size variance; sensor and engine bay harness are replaced. For the Ram 1500, FCA reports B0090-49, internal electronic failure of the left frontal acceleration sensor: after sensor replacement the part number must match the restraint controller (STAR S2408000050), and TSB 08-150-26 (2025 Ram 1500) reflashes the controller. The airbag lamp comes on.

Likely causes

Water in the left front sensor connector damaging the harness (Acura 18-016)
Replacement sensor part number not matching the restraint controller (FCA S2408000050)
Restraint controller software needing a reflash (FCA TSB 08-150-26)
Sensor damaged by a front-end impact or poor refitting after body repair

Symptoms

  • Airbag warning lamp on, often after front-end repair or water exposure
  • Frontal crash detection relies on the module's internal sensor only
  • Safety note: airbag system; disconnect the battery and observe the wait time before touching sensors or wiring, work at a specialist workshop

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–700
Time0.5–3 h

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

Parts involved

left front crash sensorsrs wiringsrs control module

Related codes

B0094B0095B0091

References: static.nhtsa.gov, static.nhtsa.gov, static.nhtsa.gov, bosch-mobility.com.