B004BThird Row Right Frontal Stage 3 Deployment Control
- Generic OBD-II code · Body
- How the car detects it
- B004B is the last code of the third-row frontal block: stage 3 of the right-hand bag. What a third element does is up to the maker. Mercedes-Benz shows one answer in its front airbags, where the third slot is a vent valve squib (B000313, B001213); Breed's patent shows another, a third chamber held back for a later second impact. Mercedes-Benz's rear airbag filing also links an extra chamber to the first through valves or throttles. No vehicle maker documents B004B and no NHTSA bulletin contains it. A fault here leaves the bag without its third element; stage 1 and 2 are B0049 and B004A. Airbag lamp on.
- What you may notice
- Airbag warning lamp on
- Right third-row airbag may deploy without its third element
- 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
- PossibleDamaged stage 3 lead or squib
- RareRestraint module configured for equipment the vehicle does not have (wrong part or coding)
- RareLoose connector in the second-row seatback
- 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.