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 and overview of each diagnostic category.

DTC Descriptors

DTC 1066: Battery Voltage Low

DTC 1067: Battery Voltage High

DTC 1068: Battery Voltage Out Of Range

Circuit/System Description

The passenger presence system (PPS) is used to monitor the pressure profile of any occupant that is sitting in the front outboard passenger seat and communicates the profile classification to the sensing and diagnostic module (SDM). The SDM will either enable or suppress the deployment of the instrument panel (I/P) module based on the profile classification of the occupant. If the PPS detects a battery voltage condition it will set DTC 202A-202E. The PPS will communicate to the SDM through a dedicated serial data circuit that a PPS fault is present. The SDM will set DTC B0081 indicating a problem within the PPS and suppress the deployment of the I/P module and illuminate the AIR BAG indicator.

Circuit/System Description

The passenger presence system (PPS) is used to monitor the pressure profile of any occupant that is sitting in the front outboard passenger seat and communicates the profile classification to the sensing and diagnostic module (SDM). The SDM will either enable or suppress the deployment of the instrument panel (I/P) module based on the profile classification of the occupant.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

The PPS module has detected supply battery voltage too low or too high.

Action Taken When the DTC Sets

    • The PPS will set a DTC and then communicate with the SDM.
    • The SDM will set DTC B0081.
    • The SDM will disable the I/P module deployment loop.
    • The PPS will illuminate the passenger air bag status OFF indicator.
    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.

Conditions for Clearing the DTC

    • The condition 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

Description and Operation

SIR System Description and Operation

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 Verification

With the passenger seat occupied and unoccupied the inflatable restraint passenger air bag on/off indicator should change states within 5 seconds.

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.

   • PPS module
   • PPS module wiring harness

  1. Verify DTC 1066-1068 is not set.
  2. If DTC 1066-1068 is set, refer to Charging System Test.
  3. Ignition OFF, disconnect the harness connector at the PPS module.
  4. Ignition OFF, test for less then 5 ohms between the ground circuit terminal 5 and ground.
  5. If greater then the specified range, test the ground circuit for an open/high resistance.
  6. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 9 and ground.
  7. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  8. If all circuits test normal, replace the PPS module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PPS module replacement, setup, and programming