The system is reporting an open circuit to the airbag, cause you let it look while it was disconnected. you need a MB specific scanner to reset it.

Since you have disconnected the battery you also have to reset a bunch of things: express windows, sunroof, possibly D2B ring, steering angle sensor, BAS/ESP codes from the steering angle sensor, clock, radio, must be others.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician