panel.
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.
Inflatable Restraint Passenger Seat Belt Tension Sensor
The seat belt tension sensor is used to enhance the Passenger Presence System (PPS) when an
infant car seat is properly restrained on the front outboard passenger seat. The seat belt tension
sensor is a 3-wire potentiometer mounted on the lower seat belt anchor and provides an input to
the PPS module. When an infant car seat is properly restrained on the front passenger seat, the
seat belt is tightly secured through the infant car seat. The seat belt pulls on the tension sensor and
changes the voltage signal to the PPS module. The PPS module uses the voltage signal to help
determine if a tightly belted infant car seat is installed. The PPS uses the inputs from the seat belt
tension sensor and the PPS pressure sensor to determine if the instrument panel (I/P) module
should be suppressed or enabled. The PPS monitors the seat belt tension sensor circuits and sets
DTC 023 if a fault is detected. To determine what DTCs have been set by the PPS, the Tech 2 is
used to command the SDM to request the PPS to flash the DTCs using the PASSENGER AIR
BAG ON/OFF indicators located on the instrument panel.
Inflatable Restraint Vehicle Rollover Sensor
The vehicle rollover sensor is used to supplement the side Supplemental Inflatable Restraint
2007 Hummer H3
2007 RESTRAINTS Supplemental Inflatable Restraints - H3