SRS Triggering Logic

The triggering logic for the SRS system is determined in the airbag control module (N2/7) in the event of a collision by the following input values:

- Actuation threshold exceeded (crash event)
Front collision (threshold 1, 2 or 3)
Side collision (threshold 1)
Rear end collision (threshold 1, 2)
Rollover (threshold 1, 2, 3)
- Switch status of belt buckles when belt buckle check is programmed
- Whether front passenger seat is occupied, sensed by front passenger seat occupied recognition sensor with automatic child seat recognition (B48)
- National version of vehicle

When the seat belt buckle check is programmed (USA) the driver and passenger airbags are actuated during a head-on collision as soon as threshold 1 is exceeded. Here the actuation conditions differ for the driver and passenger seats.

If the belt buckle check is not programmed the driver and passenger airbags are triggered only after exceeding threshold 2.

In the event of a side collision the front side airbag as well as the rear side airbag (SA) and window airbag (SA) on the affected side are triggered (exception: when passenger seat is not occupied the side airbag on the passenger side is not actuated).

Occupation status of front passenger seat occupied recognition sensor with automatic child seat recognition:

Seat not occupied:
- Passenger seat not occupied
- Child seat without transponder installed (weight of 12 kg/120 mm dia. not reached)

Seat occupied:
- Passenger seat occupied (weight of 12kg/120 mm dia. reached)

Child seat not recognized:
- MB child seat with transponder not installed
- MB child seat with transponder installed incorrectly or defective.

Child seat recognized:
- MB child seat with transponder

The child seat recognized signal has priority over the seat occupied signal (in the event that the child seat exceeds a weight of 12 kg/120 mm dia.)

With Front Passenger Seat Occupied Recognition Sensor and ACSR*:

Rear Seats:

* ACSR = Automatic Child Seat Recognition