B003ASecond Row Right Frontal Stage 2 Deployment Control
- Generic OBD-II code · Body
- How the car detects it
- B003A covers stage 2 of the right rear-seat frontal airbag. The second charge allows the module to soften or strengthen inflation; for a rear bag this matters because the person behind the front seat may be an adult, a child or a child seat facing either way, a point Mercedes-Benz stressed when it introduced the S-Class rear airbag in 2020. The Mercedes filing for a bag on a sliding front backrest provides separate deployment devices so its chambers can fire one after the other. No vehicle maker documents B003A, and no bulletin with it is on record at NHTSA. A stage 2 code alone suggests the stage 2 wires or igniter rather than the whole bag. Airbag lamp on.
- What you may notice
- Airbag warning lamp on
- Rear airbag may not adapt its inflation to the occupant
- 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
- PossibleOpen or short only in the stage 2 pair of wires
- PossibleFaulty second igniter in the right rear-seat airbag
- 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.