Rainier AWD L6-4.2L VIN S (2005)
Seat Sensor/Switch: Description and Operation
INFLATABLE RESTRAINT SEAT POSITION SENSORS (SPS)
The seat position sensor (SPS) is used to determine the proximity of a front driver or passenger seat 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 both the
driver and passenger seats. 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 codes B0083 or B0084 and
defaults to disabling stage 2 frontal deployment. This will only default on the side of the vehicle the sensor has a fault. Its important to understand that
the SPS is secondary to the passenger presence system (PPS) in the disable mode the passenger air bag will not deploy regardless of the SPS status.
