B0031Second Row Left Frontal Stage 1 Deployment Control
- Generic OBD-II code · Body
- How the car detects it
- B0031 points to the first firing stage of a frontal airbag that protects the left rear passenger, so it can only be stored where such a bag exists. The known production case is Mercedes-Benz's S-Class of 2020: an optional rear airbag (standard on the Maybach) unfolds from the back of the front seat for the two outer rear seats, built as a gas-filled tube frame that draws ambient air into its cushion. No carmaker publishes B0031 with this meaning. GM used the number differently: the Saab 9-4X 2011 manual groups B0031 with its front seat side airbag codes. Stage 2 and 3 of the same bag follow as B0032 and B0033. The airbag lamp lights and the rear bag may not fire in a frontal crash.
- What you may notice
- Airbag warning lamp on
- Left rear passenger may lose frontal airbag protection in a crash
- 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
- LikelyLoose or corroded connector of the airbag lead routed through the front seat backrest
- PossibleInternal fault in the rear-seat airbag module in the front seatback
- PossibleLead stretched or pinched by the seat track or folding mechanism
- 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.