GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Cobalt 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC B0081

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 B0081 3A: Passenger Presence System Incorrect Component Installed

DTC B0081 39: Passenger Presence System Internal Electronic Failure

DTC B0081 71: Passenger Presence System Invalid Serial Data Received

Circuit/System Description

When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. When the SDM has completed the power-up mode, the SDM will establish communication with the passenger presence system (PPS). The PPS will respond by commanding both of the PASSENGER AIR BAG ON/OFF indicators ON for 5 seconds. The SDM will then transmit a request message to the PPS to receive the PPS verification ID. The PPS will transmit the verification ID to the SDM, and the SDM will compare the ID received to data stored in memory. If the data stored in memory does not match the information transmitted by the PPS or the SDM has detects that the PPS has set a current DTC the SDM will then disable the instrument panel (I/P) module deployment loop, set DTC B0081 and command the AIR BAG indicator ON.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

All of the following conditions must exist for 5 seconds:

B0081 3A

    • The SDM has received an ID message from the PPS which does not match the ID stored in the SDM memory.
    • The SDM has reset the PPS twice without detecting the correct ID message.

B0081 39

    • The SDM has received a NOK message from the PPS.
    • The SDM has not received a message.

B0081 71

The SDM has received invalid serial data from the PPS.

Action Taken When the DTC Sets
    • The SDM commands the AIR BAG indicator ON via serial data communications.
    • The I/P module deployment loop will be disabled.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
    • A history DTC will clear once 255 malfunction-free ignition cycles have occurred.

Diagnostic Aids

If either the SDM or PPS were replaced verify that the correct part numbers were used for the vehicle application.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

SIR Connector End Views

Electrical Information Reference

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

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.

       • The PPS module
       • The SDM module
       • The PPS wiring harness connector
       • The SDM wiring harness connector

  1. Ignition ON, the PPS should turn ON the PPS ON/OFF indicators. Verify the PPS illuminates the PPS ON/OFF indicators.
    2. ⇒If the Passenger Air Bag ON/OFF status indicator does not illuminate refer to Passenger Presence System Indicator Circuit Malfunction .
  2. Ignition ON, use the scan tool. Go to the passenger presence system (PPS) menu, then retrieve the DTCs. Refer to Passenger Presence System Flash Code Procedures . Verify no PPS DTCs are set.
    3. ⇒If the PPS has any current or history DTCs stored, you must address the PPS DTCs first. Refer to the Diagnostic Trouble Code (DTC) List - Vehicle .
  3. Check to see if the PPS was replaced. Verify that the correct PPS was installed into the vehicle.
    4. ⇒ If the wrong PPS was installed then replace the correct PPS.
  4. Ignition OFF, disconnect the PPS module connector.
  5. Remove the SDM connector.
  6. Test the occupant sensor serial data circuit for an open or high resistance between the PPS and SDM connector. Verify no open or high resistance exists.
    7. ⇒If any of the above conditions are found make the appropriate repair.
  7. Test the PPS ignition 1 voltage circuit for a short to ground, a high resistance, or an open. Verify no short to ground, a high resistance, or an open exists.
    8. ⇒If any of the above conditions are found make the appropriate repair.
  8. Replace the PPS.
  9. Ignition ON, use the scan tool to clear the DTCs then recheck for DTC B0081. Verify that the DTC does not reset.
    10. ⇒If DTC B0081 resets, then replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  SIR/SRS Wiring Repairs
    •  Control Module References for PPS and SDM replacement, setup, and programming