Module - Occupant Classification: Operation

The microprocessor in the Occupant Classification Module (OCM) (2) contains the Occupant Classification System (OCS) logic circuits. The OCM uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is also used for OCS diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.

The OCM (2) provides voltage to the four seat weight sensors located on the corners of the passenger front seat (1, 3, and 4), and to the seat track position sensors on the outboard passenger and driver front seat upper seat tracks. The OCM then monitors return inputs from each of the sensors on dedicated hard wired data communication circuits. The seat weight sensor input allows the OCM to determine whether the passenger side front seat is occupied and the relative size of the occupant by providing a weight-sensing reference to the load on the seat. The seat track position sensor provides an additional logic input to the OCM microprocessor that allows it to determine the position of the front seat passenger and driver relative to the front airbags.