GM Service Manual Online
For 1990-2009 cars only

DTC Descriptors

DTC B0100 : Front End Sensor 1 Performance (Left)

DTC B0101 : Discard Front End Sensor 1 (Left)

DTC B0102 : Incorrect Front End Sensor 1 Installed (Left)

DTC B0103 : Front End Sensor 2 Performance (Right)

DTC B0104 : Discard Front End Sensor 2 (Right)

DTC B0105 : Incorrect Front End Sensor 2 Installed (Right)

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Front End Sensor Left Signal Circuit

--

--

B0100

--

--

Front End Sensor Left Voltage Circuit

B0100

B0100

B0100

B0100

B0100

Front End Sensor Right Signal Circuit

--

--

B0103

--

--

Front End Sensor Right Voltage Circuit

B0103

B0103

B0103

B0103

B0103

Circuit/System Description

The inflatable restraint front end sensor utilizes a unidirectional 2-wire circuit. The front end sensor modulates current on the interface to send ID, State of Health, and deployment commands to the inflatable restraint sensing and diagnostic module (SDM). The SDM serves as a power source and a ground for the front end sensor. When the ignition is turned ON and input power from the SDM is first detected, the SIS responds by performing internal diagnostics and sending an ID to the SDM. The SDM considers the ID to be valid if the response time is less than 5 seconds. The front end sensor continually communicates status messages to the SDM, which determines if a fault is present in the front end sensor circuit. When a fault is detected, the SDM resets the front end sensor twice by removing and reapplying power to it. If the fault is still present, the SDM will set a DTC.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

All of the following conditions exist for 2.5 seconds:

B0100 for Front End Sensor 1 or B0103 for Front End Sensor 2

    • A valid ID message is not received within 5 seconds of the front end sensor being powered up.
    • The SDM has not received a message from the front end sensor for more than 375 milliseconds.
    • The SDM has reset the front end sensor twice without detecting a valid ID message.

B0101 for Front End Sensor 1 or B0104 for Front End Sensor 2

    • The SDM has received an ID message from the front end sensor, which does not match the ID stored in the SDM memory.
    • The SDM has reset the front end sensor twice without detecting a correct ID message.

B0102 for Front End Sensor 1 or B0105 for Front End Sensor 2

The SDM has received a NOK message from the front end sensor.

Action Taken When the DTC Sets

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

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.

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

  1. Ignition ON, use the scan tool as clear SIR codes then recheck for DTCs. Verify that DTC B0101, B0102, B0104, or B0105 is not set.
  2. If DTC B0101 or B0102 is set current replace the front end sensor 1/left.
    If DTC B0104 or B0105 is set current replace the front end sensor 2/right.
  3. If DTC B0100 is current, disconnect the front end sensor 1 connector, or if DTC B0103 is current disconnect the front end sensor 2 connector. Refer to front end sensor replacement in Repair Instructions for location of connector.
  4. Remove the SDM connector, refer to SDM replacement in Repair Instructions for connector location.
  5. Test the signal and voltage circuits between the SDM and front end sensor. Verify that a short to voltage, short to ground, or open/low resistance does not exist.
  6. If any of the above conditions are found make the appropriate repair.
  7. Reconnect all SIR components. Ignition ON, use the scan tool to clear the DTCs then recheck for DTCs. Verify no DTCs are set.
  8. If DTC B0100 was current replace the front end sensor 1. After replacement refer to Repair Verification.
    If DTC B0103 was current replace the front end sensor 2. After replacement refer to Repair Verification.

Repair Instructions

Important: Always perform the Diagnostic System Check - Vehicle after completing the diagnostic procedure.

    •  Inflatable Restraint Front End Sensor Replacement
    •  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 B0100 or B0103 was current replace the SDM.