GM Service Manual Online
For 1990-2009 cars only

The scan tool used provides the following capabilities:

    • Read the data list.
    • Read current and history trouble codes.
    • Clear the diagnostic trouble codes after a repair is completed.

Make sure the scan tool contains the latest software before attempting to communicate with the SIR system. To use the scan tool, connect it to the Data Link Connector (DLC) and turn the ignition switch to the RUN position. The scan tool reads serial data sent from the inflatable restraint Sensing and Diagnostic Module (SDM) Serial Data output terminal 5 to the DLC terminal 9.

The SIR Scan Tool Data List contains all restraint related parameters that are available on the scan tool. The list is arranged in the order as they appear on the scan tool.

Use the SIR Scan Tool Data List only after the following is determined:

    • Diagnostic System Check is completed.
    • No Diagnostic Trouble Codes (DTCs) are set.
    • SIR Diagnostics indicates functioning properly.

Scan tool values from a properly operating system may be used for comparison with the SIR system you are diagnosing. The SIR Scan Tool Data List represents values seen on a properly operating system.

Important: Make sure the scan tool that you are using is functioning properly. Use of a malfunctioning scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Intermittents and Poor Connections for diagnosis.

Scan Tool Parameter

Units Displayed

Typical Data Value

Ignition ON, Engine OFF, and Driver Seat Belt Buckled

Ignition

Volts

12 V

Lamp Driver

Internal/External

External

Driver Resistance

Ohms

2.6 ohms

Passenger Resistance

Ohms

2.2 ohms

Driver Senselo

Volts

4.1 V

Passenger Senselo

Volts

4.1 V

Driver VDIF

Millivolts

4-8 mV

Passenger VDIF

Millivolts

4-8 mV

Warning Lamp ON

Hours

0-182 Hrs

Warning Lamp Cycles

Cycles

0-125 Cycles

Driver Seat Belt

Buckled/Unbuckled

Buckled