Diagnostic Instructions

DTC Descriptors

DTC B0079 01: Driver Seat Position Sensor Circuit Short to Battery

DTC B0079 02: Driver Seat Position Sensor Circuit Short to Ground

DTC B0079 05: Driver Seat Position Sensor Circuit Short to Battery or Open

DTC B0079 08: Driver Seat Position Sensor Circuit Signal Invalid

Diagnostic Fault Information

Circuit	Short to Ground	High Resistance	Open	Short to Voltage	Signal Performance
Driver Seat Position Sensor Signal	B0079 02	B0079 05	B0079 05	B0079 01	B0079 08
Driver Seat Position Sensor Low Reference	B0079 02	B0079 05	B0079 05	B0079 01	B0079 08
Passenger Seat Position Sensor Signal	B0080 02	B0080 05	B0080 05	B0080 01	B0080 08
Passenger Seat Position Sensor Low Reference	B0080 02	B0080 05	B0080 05	B0080 01	B0080 08

Circuit/System Description

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 the 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 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 code B0079 and disable stage 2 frontal deployment.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0079 01

The SDM detects the SPS circuit is shorted to voltage for 2 seconds.

B0079 05

The SDM detects the SPS circuit is shorted to voltage or open for 2 seconds.

B0079 08

The SDM detects the SPS circuit is invalid for 500  milliseconds.

B0079 02

The SDM detects the SPS circuit is shorted to ground for 2 seconds.

Action Taken When the DTC Sets

Conditions for Clearing the MIL/DTC

Reference Information

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

Circuit/System Testing

Important: When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector:

•	SDM module

•	Seat position sensor wiring harness connector

•	SDM wiring harness connector

1. Ignition OFF, disconnect the harness connector at the SPS.
2. Test for less than 1 ohm between the low reference circuit terminal B and ground.

⇒	If greater than the specified range, test the low reference an open/high resistance. If the circuit tests normal, replace the SDM.

3. Ignition ON, test for 1.2-2.0 volts between the signal circuit terminal A and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the SDM.

⇒	If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the SDM.

4. If all circuits test normal, replace the SPS.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.