Body, generic

B0073 Second Row Left Seat Belt Pretensioner Deployment Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0073 concerns the pretensioner at the left outer seat of the second row, normally built into the rear retractor. Mitsubishi documents it under exactly this name: with the ignition on, its airbag sensor unit stores B0073 with byte 11, 12, 13, 1A or 1B for a short to ground, a short to power, an open, lines shorted to each other or excessive resistance, and with byte 55 when the stored configuration does not match the vehicle; each fault must last 2 seconds. Toyota's Tundra bulletin T-SB-0057-22 lists B007311 and B007312. IIHS frontal tests with a dummy in the left rear seat show why such units are now spreading to the back row. GM uses the number differently: bulletin 22-NA-170 for the Equinox and Terrain links B0073 to water in the right front seat harness connector X320.

Likely causes

Plug at the left rear retractor loose or damaged after trim or seat removal
Harness to the left rear pretensioner shorted to ground or power
Airbag module configuration does not match the fitted rear pretensioners (Mitsubishi byte 55)
Internal fault of the left rear pretensioner or of the airbag module

Symptoms

  • Airbag warning lamp on
  • Left rear occupant gets no belt pretensioning in a crash
  • Safety note: pyrotechnic part in the rear retractor; work only with the system de-energised and preferably at a specialist workshop

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–600
Time0.5–2.5 h

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

Parts involved

second row left pretensionersquib circuitsrs control module

Related codes

B0075B007BB00E3B0053

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