B0042Third Row Left Frontal Stage 2 Deployment Control
- Generic OBD-II code · Body
- How the car detects it
- B0042 stands for the second stage of a frontal airbag aimed at the left third-row passenger. A second stage only makes sense with an inflator that has two independently fired charges, as in Breed's multi-chamber design where the controller picks which chamber fires first and the gap between them. No carmaker documents B0042 for the third row, and no series car with such a bag is known. The older GM meaning is clear-cut: Saab's 9-5 (2006) and 9-3 manuals define B0042 as driver frontal stage 2 loop resistance below 1.5 ohms lasting 2 seconds, and the GM CPA retainer bulletin 08-09-41-002H covers it too. Airbag lamp on.
- What you may notice
- Airbag warning lamp on
- Adaptive two-stage inflation for this seat is unavailable
- Safety note: do not probe the airbag circuit yourself; unplug airbag connectors only with the battery disconnected and the stated wait time observed
- Likely causes
- PossibleOpen or short only in the stage 2 wiring
- PossibleConnector lock not engaged at the airbag plug
- RareRestraint module configured for equipment the vehicle does not have (wrong part or coding)
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.