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 B1000: Internal SDM Failure

Circuit/System Description

This DTC identifies a malfunction within the sensing and diagnostic module (SDM).

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

An internal SDM malfunction exists.

Action Taken When the DTC Sets

    • The SDM commands the AIR BAG indicator ON.
    • The SIR System is disabled and no deployments are allowed.

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

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

Important: Refer to SIR Service Precautions .

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

   • The front end sensor
   • The SDM module
   • The front end sensor wiring harness connector
   • The SDM wiring harness connector

  1. Are other DTCs current in addition to B1000?
  2. Go to applicable DTC. Refer to Diagnostic Trouble Code (DTC) List - Vehicle
  3. Turn OFF the ignition.
  4. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection .
  5. Wait 90 seconds, then connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection .
  6. Wait at least 2 seconds, then turn ON the ignition, with the engine OFF.
  7. Wait at least 60 seconds, then clear any stored DTCs.
  8. Turn OFF the ignition.
  9. Turn ON the ignition, with the engine OFF.
  10. Wait at least 60 seconds, then check if DTC B1000 is present.
  11. If DTC B1000 is present, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Inflatable Restraint Front End Sensor Replacement
    •  Inflatable Restraint Side Impact Sensor Replacement
    •  SIR/SRS Wiring Repairs
    •  Control Module References for SDM replacement, setup, and programming