WSS control unit, task - GF91.60-P-4105-02QM
The WSS (Weight Sensing System) control unit (N2/13) determines the weight (person or child seat) resting on the front passenger seat by evaluating the input from the following sensors:
- Belt tension sensor (B48/3)
- Pressure sensor (B48/4)
The pressure sensor (B48/4) transmits the data on the amount of pressure exerted on the gel mat to the WSS (Weight Sensing System) control unit (N2/13) via a discrete line. In addition, the belt force at the belt tension sensor (B48/3) is read in by the WSS (Weight Sensing System) control unit via a discrete line (N2/13). Based on the input from both sensors, the WSS (Weight Sensing System) control unit (N2/13) detects the difference between a person and a child seat, since with a child seat there is a significantly greater force measured at the belt tension sensor (B48/3) than with persons. The WSS (Weight Sensing System) control unit (N2/13) transmits this data over the Controller Area Network Bus Class B (interior) (CAN-B) to the restraint systems control unit (N2/7).
If the front passenger seat is unoccupied or has a child seat on it, the front passenger airbag and the associated emergency tensioning retractor (ETR) are not actuated.
The WSS (Weight Sensing System) control unit (N2/13) essentially performs the following tasks:
- Supply power to and read data from the pressure sensor (B48/4) and the belt tension sensor (B48/3)
- Calculate the weight classification to distinguish whether the seat is occupied by a person or a child seat
- Send the weight data to CAN-B
- Self-test of the WSS (Weight Sensing System) control unit (N2/13) (with "Circuit 15 ON" and with entries stored in the fault memory)
Any work on the WSS (Weight Sensing System) control unit (N2/13) must only be done with "Circuit 15C OFF"; otherwise, the calibration of the WSS (Weight Sensing System) control unit (N2/13) will be influenced, which could cause the system to make incorrect evaluations.