The inflatable restraint 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 near the seat track of both the driver and passenger seats. The seat track includes a metal bracket that shunts the SPS magnetic circuit creating 2 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) and the manual instrument panel (I/P) module disable switch. If either one of these devices are in the disable mode the passenger air bag will not deploy regardless of the SPS status.

Ignition voltage is between 9-16 volts.

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Driver Seat Position Sensor parameter and Passenger Seat Position Sensor parameter while commanding the appropriate seat BACKWARD and FORWARD, the reading should change between Rearward and Forward.

1. Ignition OFF, disconnect the harness connector at the appropriate inflatable restraint seat position sensor.
2. Disconnect the harness connector at the SDM.
3. Ignition ON, test for less than 1 volt between the appropriate inflatable restraint seat position sensor circuit terminal A and ground.

⇒	If greater than the specified value, test the circuit for a short to voltage.

4. Test for less than 1 volt between the appropriate inflatable restraint seat position sensor circuit terminal A and ground.

⇒	If greater than the specified range, test the circuit for a short to voltage.

5. Ignition OFF, test for infinite resistance between the appropriate inflatable restraint seat position sensor circuit terminal B and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground.

6. Test for less then 1 ohm between the following inflatable restraint seat position sensor circuit terminals:

•	Passenger seat position sensor terminal B and SDM terminal 28.

•	Driver seat position sensor terminal B and SDM terminal 28.

⇒	If greater than the specified range, test the circuit for an open/high resistance.

7. Test for less then 1 ohm between the following inflatable restraint seat position sensor circuit terminals:

•	Passenger seat position sensor terminal A and SDM terminal 30.

•	Driver seat position sensor terminal A and SDM terminal 29.

⇒	If greater than the specified range, test the circuit for an open/high resistance.

8. If all circuits test normal, replace the appropriate inflatable restraint seat position sensor.
9. Reconnect the harness connector at the SDM and appropriate inflatable restraint seat position sensor.
10. Ignition ON, with a scan tool clear and recheck for DTCs.

⇒	If the seat position sensor DTC resets and is current, replace the SDM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.