Seat Track Position Sensor: Operation

The seat track position sensor is designed to provide a seat position data input to the Occupant Classification Module (OCM) indicating whether the driver side front seat is in a full forward or a not full forward position. The OCM sends electronic seat position  messages to the Occupant Restraint Controller (ORC) over the Controller Area Network (CAN) data bus. The ORC uses this data as an additional logic input for use in determining the appropriate deployment force to be used when deploying the multistage front airbags.

The seat track position sensor receives a nominal five volt supply from the OCM. The sensor communicates the seat position by modulating the voltage returned to the OCM on a sensor data circuit. The OCM also monitors the condition of the sensor circuits and will store a Diagnostic Trouble Code (DTC) for any fault that is detected, then sends a message to the ORC to illuminate the airbag indicator in the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN).

The hard wired circuits between the seat track position sensor and the OCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the SYSTEM WIRING DIAGRAMS article. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the seat track position sensor or the electronic controls and communication between other modules and devices that provide features of the supplemental restraint system. The most reliable, efficient, and accurate means to diagnose the seat track position sensor or the electronic controls and communication related to seat track position sensor operation requires the use of a diagnostic scan tool. Refer to the appropriate ELECTRICAL DIAGNOSTIC article.