What the airbag control unit does on your Mercedes
Mercedes-Benz names its airbag control unit just that, the airbag control unit, sometimes called the SRS control module. It is the brain of the restraint system, reading the impact sensors, deciding when to fire the airbags and the belt pretensioners, and writing a permanent record of any deployment into its memory. Across the C-Class, E-Class, and the GLC and GLE, Mercedes sources these modules from suppliers like Bosch, Continental, and TRW, so the exact board varies by chassis even when the job is the same.
Once the crash data is written, the module locks and the airbag light stays on. Even a minor collision that never deploys an airbag can lock the belts and leave the unit holding crash codes. A standard OBD scanner cannot erase that data, because it sits in the module's own memory. We take your original Mercedes airbag control unit in our shop, clear the stored crash data and hard codes, and send it back reading factory-ready. It keeps its original coding, so it plugs straight back in and works the moment you reinstall it, at a fraction of the dealer price for a new unit.
