Body, generic

B0022 Left Curtain Deployment Control 2

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

B0022 belongs to a second firing loop for the left curtain airbag. Mercedes-Benz shows what that means in practice: on the A-Class, CLA and GLB, B002213 is an open squib in the left rear window bag, the curtain section for the rear seats, while B0021 serves the front one (LI54.21-P-070658, version 1 of 2019 and version 4 of 2020). Cars with a single curtain inflator never set it. General Motors has older meanings for the number: the 2006 Saab 9-5 used it for driver frontal stage 1 resistance below 2.0 ohms, and Global A modules for the passenger belt retractor pretensioner, as on the 2009-11 Impala (PIC5396A) or the Saab 9-4X. The module and descriptor shown by the scan tool decide which part is meant. Airbag lamp on.

Likely causes

Raised contact resistance at the restraint module connector (Mercedes LI54.21-P-070658)
Damaged lead to the rear curtain section at the C-pillar or roof rail
Internal fault in the rear left curtain airbag module
Fault or unsuitable software in the restraint control module

Symptoms

  • Airbag warning lamp on
  • Head protection for the left rear seat may be missing
  • Safety note: do not probe the airbag circuit yourself; unplug airbag connectors only with the battery disconnected and the stated wait time observed

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–1,000
Time1–4 h

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

Parts involved

left curtain airbagsrs roof wiringsrs control module

Related codes

B0021B002AB0046

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