Body, generic

B0003 Driver Frontal Stage 3 Deployment Control

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Some driver airbag modules carry a third pyrotechnic element in addition to the two inflator stages, and B0003 covers its firing loop. FCA lists the code as driver frontal squib 3; its STAR case S2108000180 found B0003-2B (wires shorted together) next to B0001 and B0002 when connector locks behind the steering wheel were not engaged. Mercedes-Benz uses B000313 for the squib of the vent valve inside the driver airbag, which lets gas escape so the cushion becomes softer. An FCA patent describes such an active vent that the airbag electronics opens or keeps closed using data from occupant classification. With this loop faulted, the bag loses its third stage or adaptive venting, while the two inflator stages may still work. The airbag lamp lights up.

Likely causes

Connector position assurance lock at the airbag module not engaged
Third squib or vent valve squib in the airbag module faulty
Damaged clock spring conductor for the third circuit

Symptoms

  • Airbag warning lamp on, often together with B0001 or B0002
  • Adaptive venting or third deployment stage unavailable
  • 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€80–1,200
Time0.5–3 h

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

Parts involved

driver airbag moduleclock springsrs wiringsrs control module

Related codes

B0001B0002B0012

References: static.nhtsa.gov, static.nhtsa.gov, patents.google.com.