Brief description of components: Notes

The following sensors detect the direction and severity of an impact:

• Acceleration sensors in the MRS control unit 

  There is a lateral acceleration sensor and a longitudinal acceleration sensor in the MRS control unit. The sensors are arranged at 90 degrees to each other.

• Airbag sensors on left-hand B-pillar and right-hand B-pillar 

  Each of the airbag sensors on the B-pillars contains a lateral-acceleration sensor and a longitudinal-acceleration sensor. The sensors are arranged at 90 degrees to each other.

• Front airbag sensors 

  The 2 front airbag sensors are longitudinal acceleration sensors.

• Airbag sensors on front left door and front right door 

  The 2 airbag sensors are pressure sensors.

  The following components provide additional input signals for the multiple restraint system:

• Passenger seat occupancy detector 

  Statutory guidelines in the USA stipulate that the seat occupancy detector mat integrated into the front-passenger seat must be able to recognize a child seated in a rearward-facing child seat. Upon detection, the airbags on the passenger side are automatically deactivated (passenger airbag and side airbag). The indicator lamp for passenger airbag deactivation lights up.

  The seat-occupancy detector evaluates the impression caused from a load on the seat.

  If the multiple restraint system (MRS) triggers the airbags and the front-passenger seat is unoccupied, the front-passenger airbag and the side airbag on the front-passenger side will not be triggered.

  The head-level airbag will still be triggered.

• Seat-belt buckle switch for driver's seat and front-passenger seat 

  The MRS control unit uses the signals from the driver's seat-belt buckle switch and the front-passenger seat-belt buckle switch to detect whether or not the seat belts are fastened.

  If the seat belt is fastened, the seat-belt tensioner will also be triggered (only in the event of frontal impact or a rear-end collision).

  The following control units are involved in the function of the MRS:

• MRS control unit 

  All triggering circuits and sensors in the multiple restraint system (MRS) are connected directly to the MRS control unit.

  The MRS control unit evaluates the data it receives from the sensors. In the event of a collision (head-on, rear-end or side impact), the MRS control unit will decide whether the seat-belt tensioners and airbags need to be triggered, and which airbags need to be triggered.

• DME: Digital engine electronics 

  Depending on accident severity, the electric fuel pump will be switched off by the DME.

  Signal path:

  MRS control unit -> K-bus -> General module -> K-bus -> Instrument cluster -> PT-CAN -> DME -> Direct wire -> Fuel-pump relay -> Electric fuel pump

• Instrument cluster 

  The instrument cluster generates the optical and audible seat-belt warning.

  When terminal R is ON, the instrument cluster receives the status message from the MRS control unit via the K-bus. Depending on the status, the optical and audible warning is triggered when terminal 15 is ON.

• GM: General module 

  The general module is connected to the MRS control unit via the K-bus.

  The general module is the executing control unit for the central locking system. The general module also controls the interior and exterior lighting.

  Depending on severity, the central locking is unlocked in the event of an accident. The interior lights and the hazard warning lights are automatically switched on.

  Signal path: MRS control unit -> K-bus -> General module

  The following components are activated by the MRS control unit:

• Multiple restraint system triggering circuits 

  With maximum equipment, the MRS (multiple restraint system) comprises the following triggering circuits:

  • Driver's airbag (stage 1)
  • Front-passenger airbag (stage 1)
  • Driver's airbag (stage 2)
  • Front-passenger airbag (stage 2)
  • Side airbag in driver's seat
  • Side airbag in front-passenger seat
  • Head-level airbag, left (optional)
  • Head-level airbag, right (optional)
  • Belt tensioner, front left
  • Belt tensioner, front right
  • Safety battery terminal