0X930979: Driver Side Airbag Circuit

Circuit fault

What 0X930979 means

A side airbag deploys out of the seat side and fills the space between the occupant's torso and the door in a side impact. Because it lives in the seat, its wiring is part of the seat harness rather than the body harness. The ACSM monitors the squib circuit, and a reading of chassis ground on either conductor is logged as 0X930979.

Seat mounted airbags are the ones most often disturbed by work that has nothing to do with the restraint system. Seat removal for carpet repair, seat heater installs, upholstery changes, and aftermarket seat covers all put hands near that harness. The connector at the floor is the usual suspect, since it gets unplugged every time the seat comes out of the car.

Common causes

• A seat floor connector that was not fully latched after the seat was reinstalled
• Harness crushed under the seat rail or caught in the seat track mechanism
• Wiring worn through against the seat frame where it flexes with seat movement
• Corrosion at the seat connector from carpet that stayed wet
• An internally shorted side airbag inflator in the seat bolster
• Damage from aftermarket seat covers or upholstery work done over the airbag seam

Crash data or hardware fault?

0X930979 is a live circuit fault, which means the module is describing a condition it can measure and can stop measuring once the repair is made. Crash data is the opposite kind of entry. It is written the moment a bag deploys, it is not a measurement at all, and no scan tool clear reaches it.

Does our reset clear it?

A module reset does not repair seat wiring, so start with the harness. Once the side airbag circuit reads in range the code clears with a normal code erase. If the side airbag has already deployed, the seat needs a genuine OEM replacement bag and the ACSM is almost certainly locked with crash data. Mail us the module and we clear that stored record after the seat work is done.

Which makes throw it

BMW uses 0X930979 for the driver side airbag circuit. The hex numbering is BMW diagnostic software, and the code applies across BMW models with seat mounted side airbags and an ACSM.

What to do next

Unlatch and reseat the connector under the driver seat first, because a plug that was never fully pushed home is the most common answer and takes a minute to rule out. Then run the seat through its travel and watch for the fault to appear. A short that stays with the airbag once the harness is disconnected means the bag is bad, and we stock genuine OEM BMW seat side airbags. Related codes: 0X930961, 0X930985, B0021-13.