GF91.60-D-0002HL Supplemental Restraint System (SRS), Function

GF91.60-D-0002HL Supplemental Restraint System (SRS), Function

- except CODE (SH6) Thorax bag for driver (in seat backrest)
- except CODE (SH7) Thorax bag for driver and front passenger (in seat backrest)
- except CODE (SH9) Window bag for driver and front passenger

The Supplemental Restraint System (SRS) serves to protect vehicle occupants from injury in various types of accidents. The vehicle's SRS comprises the following airbag and belt tensioning units:
- Driver emergency tensioning retractor unit with driver GUS squib (R12/1)
- Front passenger emergency tensioning retractor unit with front passenger GUS squib (R12/2)
- Driver airbag with driver airbag squib (R12/3)
- Front passenger airbag with front passenger airbag squib (R12/4)
- Center front passenger emergency tensioning retractor unit with center front passenger GUS squib (R12/34)

The Lowline airbag control unit (N2/14) triggers the front airbag and emergency tensioning retractor units necessary to provide optimum passenger protection depending on the type and severity of the accident. In the process, the acceleration values of the sensors integrated in the Lowline airbag control unit are taken into consideration as input variables.

With the driver seat, the switched status of the driver seat belt buckle switch (S68/1) is additionally taken into account. In the case of rear-end collisions and minor front-end collisions, only the emergency tensioning retractors are triggered. In the case of more severe front-end collisions, the front airbags are also triggered.

At the same time as the respective airbag and emergency tensioning retractor units are triggered, the Lowline airbag control unit issues an accident signal to various control units:
- To the ME control unit (N3/23) for switching off engine 272. The accident signal is sent via the Controller Area Network bus class B (interior) (CAN-B) to the EZS control unit (N73) and from there via the Controller Area Network Bus class C (engine compartment) (CAN-C) to the ME control unit.
- To the CDI control unit (N3/21) for switching off engine 646 or to the CDI control unit (N3/20) for switching off engine 642. The accident signal is sent via CAN-B to the EZS control unit and from there via CAN-C to the respective CDI control unit.
- To the driver door control unit (N69/1) for emergency opening the driver door via CAN-B.
- On vehicles with code (H12) Auxiliary heater (warm water) or with code (HZ5) 10 kW warm water auxiliary heater with timer to the warm water auxiliary heating control unit (N33/3) for shutting off the fuel-operated stationary heater via CAN-B.
- To the SAM control unit (N10) for emergency opening the right or left sliding door and the rear-end door as well as for actuating the hazard warning system. The hazard warning system can be switched off again via the hazard warning system switch (N72/1s6).
- To the EZS control unit for opening all doors redundantly and for transmitting the crash signal to CAN-C for shutting off the engine.

As a "function check" is not possible for the SRS, we will refrain here from providing a description of the individual triggering strategies.

Furthermore, the triggering strategies are subject to modifications, such as those resulting from new knowledge gained in the area of accident research.

System monitoring

SRS malfunctions are indicated by the SRS warning lamp (A1e22) and the multifunction display in the instrument cluster (A1). For this purpose, the instrument cluster receives the corresponding message from the Lowline airbag control unit via CAN-B.

Diagnosis

Diagnosis takes place via STAR DIAGNOSIS.

Disposal

When handling and disposing of airbag and emergency tensioning retractor units, the corresponding safety and disposal information in the work instructions must be fully observed.