0X930949: Driver Knee Airbag Circuit

Circuit fault

What 0X930949 means

A knee airbag keeps the occupant's hips and legs from submarining under the belt during a frontal crash, which helps the front airbag do its job correctly. It has a squib like any other inflator, and the ACSM monitors that squib's circuit for resistance and for unwanted contact with ground or power. A ground reading on either wire puts 0X930949 in memory.

Knee airbag wiring is exposed to a part of the cabin that gets a lot of traffic. The harness runs across the lower dash right where knee bolster panels come off for column work, fuse box access, and pedal assembly service. Shoes, floor mats, and anything stored in the footwell can also reach a connector that was left hanging instead of clipped up.

Common causes

• A knee bolster panel reinstalled with the airbag harness pinched behind it
• Connector left unclipped and resting against the steering column bracket
• Wiring chafed against a sharp bracket edge under the dash
• Water from a heater core leak or windshield leak reaching the footwell harness
• An internally shorted knee airbag inflator
• Damage during column, pedal, or fuse box service

Crash data or hardware fault?

This entry describes an electrical state the module can measure, so it belongs with live faults. Correct the short and the code stops coming back. Stored crash data is the other category, created only when the restraints deploy, and it stays written in the module permanently no matter what the wiring does afterward.

Does our reset clear it?

Do not reach for a reset on a live short. The ACSM performs its check and rewrites 0X930949 within seconds of the next key cycle. Repair the harness or replace the bag, then clear. On a BMW that was wrecked and had the knee airbag deploy, the module will also be holding crash data, and our mail-in reset service clears that after the replacement bag is installed.

Which makes throw it

0X930949 appears on BMW models equipped with a driver knee airbag. The hex code format belongs to BMW diagnostic software, so other brands describe the same component under different numbering.

What to do next

Pull the lower dash trim and look at how the harness was routed the last time somebody was in there, since a pinched wire behind a bolster panel is the most common cause. Unplug the knee airbag and remeasure to separate bag from harness. If the inflator is shorted internally, the assembly needs replacing and we carry genuine OEM BMW knee airbags. Related codes: 0X930937, 0X930955, B0022.