GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0083: Right Front Seat Position Sensor Circuit

DTC B0084: Left Front Seat Position Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Seat Position Sensor Left Low Reference

B0084

B0084

B0084

B0084

B0084

Seat Position Sensor Left Signal

B0084

B0084

B0084

B0084

B0084

Seat Position Sensor Right Low Reference

B0083

B0083

B0083

B0083

B0083

Seat Position Sensor Right Signal

B0083

B0083

B0083

B0083

B0083

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 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 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.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0083 for Right Front Seat Position Sensor or B0084 for Left Front Seat Position Sensor

    • The SDM detects the SPS circuit amperage is 4 mA or less for 500 milliseconds.
    • The SDM detects the SPS circuit amperage is between 8-11 mA for 500 milliseconds.
    • The SDM detects the SPS circuit amperage is 18 mA or greater for 500 milliseconds.

Action Taken When the DTC Sets

    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
    •  The SDM defaults the SPS to seat forward threshold.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

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.

       • Seat position sensor
       • SDM module
       • Seat position sensor wiring harness connector
       • SDM wiring harness connector

  1. Ignition OFF, disconnect the applicable seat position sensor connector.
  2. Disconnect the harness connector at the SDM.
  3. Ignition ON, test for less than 1 volt between the seat position sensor signal circuit terminal A and ground.
  4. If greater than the specified range, test the circuit for a short to voltage.
  5. Ignition ON, test for less than 1 volt between the applicable seat position sensor low reference circuit terminal B and ground.
  6. If greater than the specified range, test the circuit for a short to voltage.
  7. Test for infinite resistance between the seat position sensor signal circuit terminal A and ground.
  8. If less than the specified range, test the circuit for a short to ground.
  9. Test for infinite resistance between the seat position sensor signal terminal B and ground.
  10. If less than the specified value, test the circuit for a short to ground.
  11. Test for less then 1 ohm of resistance between the following seat position sensor signal circuit terminals.
  12. • Passenger seat position sensor terminal A and SDM harness connector terminal 25.
    • Driver seat position sensor terminal A and SDM harness connector terminal 24.
    If greater than the specified range, test the circuit for an open/high resistance.
  13. Test for less then 1 ohm between the following seat position sensor low reference circuit terminals.
  14. • Passenger seat position sensor terminal B and SDM harness connector terminal 11.
    • Driver seat position sensor terminal B and SDM harness connector terminal 11.
    If greater than the specified range, test the circuit for an open/high resistance.
  15. If all circuits test normal, replace the applicable front end sensor.
  16. Reconnect all SIR components. Ignition ON, with a scan tool clear and recheck for DTCs.
  17. If the seat position sensor DTC returns and is current, replace the SDM.

Repair Instructions

    •  Inflatable Restraint Seat Position Sensor Replacement
    •  SIR/SRS Wiring Repairs
    •  Control Module References for SDM replacement, setup, and programming

Repair Verification

Ignition ON, use the scan tool to clear the DTCs then recheck for DTCs. Verify no DTCs are set.

If DTC B0083 or B0084 was current replace the SDM.