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

MODEL 453.3/4 

with CODE 494 (US version) 

G12097218Courtesy of MERCEDES-BENZ USA

Function requirements, general 

The circuit 15 status of the ignition lock (S2) is received by the Weight Sensing System (WSS) control unit over a direct line from the vehicle interior fuse and relay module (F2).

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. Occupancy of the front passenger seat is recorded by the front passenger seat occupancy recognition seat mat (1) by the WSS control unit. The WSS control unit sends the status over the seat occupancy LIN (LIN E2) to the supplemental restraint system control unit (N2/10). The passenger-side seat occupied recognition function includes the following subfunctions:

Function sequence for evaluation of occupancy status of front passenger seat 

Occupation of the front passenger seat by a person or a child seat is determined by the weight, which is applied to the front passenger seat.

The WSS control unit registers the weight applied by measuring the pressure in the front passenger seat occupancy recognition seat mat (1) filled with gel. The pressure sensor required for this is integrated in the WSS control unit. The WSS control unit performs a weight classification. The WSS control unit signals are read in over the seat occupancy LIN from the SRS control unit. The following conditions are defined depending on the weight classification:

IMPORTANT The occupancy status of the front passenger seat, which is detected by the front passenger seat occupancy recognition seat mat (1) and the WSS control unit, in vehicles with code 494 (USA version) exerts an influence on the SRS deployment characteristics. Vehicles with code 460 (Canada version) are always assigned code 494 (USA version) at the same time and therefore they have the same SRS safety equipment.

Function sequence for issuing status and fault messages 

Additional function requirements

IMPORTANT Information about the indicator lamp self-test can be found in the subfunction "Supplemental restraint system triggering function" in the "System monitoring function sequence" chapter.

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, is shown when the front passenger airbag is activated by the SRS control unit thereby rendering it operational. If the front passenger airbag was deactivated by the SRS control unit, this is then 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. The occupancy status of the front passenger seat is shown as follows:

Front passenger airbag ON indicator lamp in the front passenger airbag warning indicator lights up.

Front passenger airbag OFF indicator lamp in the front passenger airbag warning indicator lights up.

Fault messages: 

In the event of a fault (e.g. WSS control unit defective or connection interference to SRS) the following indicator lamps are switched on:

In vehicles with code K36 (Instrument cluster with color 8.9 cm (3.5") display), in the event of a fault the warning "Fault: Service Required" is also displayed via the multifunction display (A1 p13) in the instrument cluster. The request to display the message is transmitted by the SRS control unit over the interior CAN (CAN B) to the instrument cluster. The faults are stored in the nonvolatile memory of the SRS control unit.

  Electrical function schematic for deployment of supplemental restraint system Model 453.3 (except 453.391), 453.4 (except 453.491) PE91.60-P-2055-97BBU 
Model 453.391/491 PE91.60-P-2055-97BEU 
  Table of contents for function description of supplemental restraint system function   GF91.60-P-0996KJU 
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