Seat Position Sensors

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The seat position sensors are used to determine the proximity of a front driver or passenger seat position with respect to the front air bag. Each seat position sensor interfaces with the inflatable restraint sensing and diagnostic module (SDM). The state of the seat position sensor allows the SDM to disable stage 2 of the front air bag for a front seat that is forward of the forward/rearward point in the seat track travel. The seat position sensor is a hall effect sensor that is mounted on the outboard seat track of the driver and passenger seats. The seat track includes a metal bracket that shunts the seat position sensor magnetic circuit creating 2 states of seat position, the shunted state represents a rearward seat position and the non-shunted state represents a forward position. The seat position sensor provides 2 current ranges, one range for the shunted state and a second range for a non-shunted state which are inputs to the SDM. When the SDM receives input from a seat position sensor that state 1 threshold is reached (seat is rearward), the SDM will enable stage 2 deployment. When state 2 threshold is reached (seat is forward), the SDM will disable stage 2 deployment on the side the seat is forward. The SDM monitors the seat position sensor circuit and if a fault is detected, the SDM will set code B0079 and disable stage 2 frontal deployment.