Yukon Denali AWD V8-6.2L (2007)
Seat Position Sensor: Description and Operation
INFLATABLE RESTRAINT SEAT POSITION SENSORS (SPS)
The seat position sensor (SPS) is used to determine the proximity of a front driver position with respect to the frontal air bag. The SPS interfaces with the
sensing and diagnostic module (SDM). The state of the SPS allows the SDM to disable stage 2 of the frontal air bag for a front seat that is forward of a
forward/rearward point in seat track travel. The SPS is a Hall effect sensor that is mounted on the outboard seat track of the driver seat. The seat track
includes a metal bracket that shunts the SPS magnetic circuit creating two states of seat position. The shunted state represents a rearward seat position.
The non-shunted state represents a forward position. The SPS provides 2 current ranges, one range for the shunted state and a second range for a
non-shunted state. These 2 states are inputs to the SDM. State 1 (shunted) being the rearward threshold and state 2 (non-shunted) being the forward
threshold. When the SDM receives input from a SPS that state 1 threshold is reached (seat is rearward) the SDM will not disable stage 2 deployment, if
required by the deployment sensors. 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 SPS circuit and if a fault is detected the SDM will set code B0079 and defaults to disabling stage 2 frontal deployment.
