Seat Weight Sensor: Operation

The seat weight sensor units are designed to sense the relative weight of a load applied to the passenger side front seat, which provides a logic input to the microprocessor of the Occupant Classification Module (OCM). When a load is applied to the seat, the strain gauge of each sensor is flexed causing a change of electrical resistance through the strain gauge. These changes in resistance are measured by the sensor and the internal sensor circuitry changes the sensor output voltage.

Each weight sensor receives a nominal five volts and a ground through parallel hard wired circuits from the OCM. The OCM then monitors the output voltage of each sensor on dedicated hard wired data communication circuits. The hard wired circuits between the sensors and the OCM may be diagnosed and tested using conventional diagnostic tools and procedures. However, the most reliable, efficient, and accurate means to diagnose the seat weight sensor inputs to the OCM, and the electronic message communication between the OCM and the Occupant Restraint Controller (ORC) requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.