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Passenger-Side Seat Occupied Recognition Function - GF91.60-P-1100KJ

MODEL 453.0/3/4 

except CODE 494 (US version) 

G12097217Courtesy of MERCEDES-BENZ USA

Function requirements, general 

The status of circuit 15 of the ignition lock (S2) is received by the supplemental restraint system control unit (N2/10) from the vehicle interior fuse and relay module (F2) via a direct line.

Passenger-side seat occupied recognition, general 

The supplemental restraint system (SRS) monitors the occupancy of the front passenger seat and the status of the front seat belts (worn or not being worn) and adapts its deployment behavior on the basis of this information. The occupancy of the front passenger seat is recorded by the SRS control unit. The passenger-side seat occupied recognition function includes the following subfunctions:

Function sequence for evaluation of occupancy status of front passenger seat 

The occupancy of the front passenger seat is detected by the front passenger seat occupancy recognition. However, only the status of the front passenger airbag shutoff switch has an influence on the deployment behavior of the SRS. If a child seat is being used, the front passenger airbag unit can be deactivated via the front passenger airbag shutoff switch. In order to do this, the front passenger airbag shutoff switch must be manually changed over by pressing and rotating at the same time. This can only be done with the front passenger door open.

The front passenger airbag shutoff switch is read in by the SRS control unit via a direct electrical line. The switch position is detected by the SRS control unit via the electrical resistance of the front passenger airbag shutoff switch. If the front passenger airbag shutoff switch is moved to the "OFF" position, the resistance is 100 Ω. If the front passenger airbag shutoff switch is moved to the "ON" position, the resistance is 400 Ω.

IMPORTANT The occupancy status of the front passenger seat, which is detected by the front passenger seat occupancy recognition, has no influence whatsoever on the deployment behavior of the SRS. The status of the front passenger seat occupancy recognition is only needed by the instrument cluster (A1) for the seat belt reminder warning.

Function sequence for issuing status and fault messages 

When circuit 15 is switched on, the following indicator lamps are actuated with regard to the front passenger seat occupancy:

After a successful self-test (t = 4 s) the SRS indicator lamp is switched off, and if the front passenger airbag is switched on the front passenger airbag OFF indicator lamp is switched off. The front passenger airbag ON indicator lamp in the front passenger airbag warning indicator indicates when the front passenger airbag is switched on via the front passenger airbag shutoff switch. If the front passenger airbag has been deactivated via the front passenger airbag shutoff switch, this is indicated by the front passenger airbag OFF indicator lamp. The front passenger airbag OFF indicator lamp and the front passenger airbag ON indicator lamp are actuated via direct lines by the SRS control unit. The SRS control unit continues to constantly monitor the seat occupancy recognition of the SRS when driving and actuates the SRS indicator lamp in the instrument cluster in the event of faults. If a defective value is detected, the SRS control unit transmits the request to actuate the SRS indicator lamp via the interior CAN (CAN B) to the instrument cluster, which then actuates the SRS indicator lamp. The SRS control unit also actuates the front passenger airbag OFF indicator lamp and switches off the front passenger airbag. If the SRS control unit detects a status change of the front passenger airbag shutoff switch while driving (v ≥ 0.5 km/h), the SRS indicator lamp is actuated and the last status of the front passenger airbag shutoff switch when the vehicle was stationary is evaluated as valid. In accordance with the last status to be recognized as valid, the front passenger airbag OFF indicator lamp or the front passenger airbag ON indicator lamp continues to be actuated, and the front passenger airbag remains switched on or off in accordance with the last valid status.

  Electrical function schematic for deployment of supplemental restraint system Model 453.0 (except 453.091), 453.3 (except 453.391), 453.4 (except 453.491) PE91.60-P-2055-97BBA 
Model 453.091/391/491 PE91.60-P-2055-97BEA 
  Overview of system components for supplemental restraint system   GF91.60-P-9996KJ