Restraint systems control unit, component description - GF91.60-P-4048MCU

MODEL 451.3 /4

Location

The restraint systems control unit is in the center on the underside of the crossmember beneath the instrument panel.

Fig 1: Locating Restraint Systems Control Unit

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

General

The restraint systems control unit controls the supplemental restraint system and is a subscriber on the Controller Area Network (data bus/CAN bus) (CAN). If an accident occurs, the restraint systems control unit specifically deploys the restraint units. This includes the airbag units and the emergency tensioning retractor units. The restraint systems control unit has self-monitoring and fault monitoring features.

Frontal, side-on and rear-end collisions and a rollover along the longitudinal vehicle axis are detected and differentiated.

Scope of tasks

Self-test and continuous monitoring of supplemental restraint system
Storage of faults that have occurred
Fault output via the diagnosis communication
System readiness indication via CAN to the instrument cluster (A1)
Power supply
- Driver head/thoraxbag sensor (A53)
- Front passenger head/thoraxbag sensor (A54)
- Driver-side frontal acceleration sensor (B48/1)
- Passenger-side frontal acceleration sensor (B48/2)
Accident detection and ignition time determination
Restraint equipment triggering
Capacitor for the event of a battery disconnection in the event of a collision
Evaluation of the sensor integrated in the restraint systems control unit
Seat belt reminder warning request
Evaluation of front passenger seat occupied recognition

Direct entries

Tml. 15
Tml. 31
Driver head/thoraxbag sensor
Front passenger head/thoraxbag sensor
Driver-side frontal acceleration sensor
Passenger-side frontal acceleration sensor
Driver side seat belt buckle restraint systems switch (S68/3)
Front passenger-side seat belt buckle restraint systems switch (S68/4)

Direct outputs

Left ETR squib (R12/1)
Right ETR squib (R12/2)
Passenger airbag squib 1 (R12/4)
Passenger airbag squib 2 (R12/5)
Driver airbag squib 1 (R12/13)
Driver airbag squib 2 (R12/14)
Driver head/thoraxbag squib (R12/20)
Front passenger head/thoraxbag squib (R12/21)
Automatic child seat recognition airbag OFF indicator lamp (E16)