GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The inflatable restraint side impact sensor (SIS) - Left loop is a 2 wire circuit. When you first turn ON the ignition, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM provides input power to the SIS. When input power is first detected, the SIS responds by performing internal diagnostics. Next the SIS sends an ID message to the SDM. The SDM will consider this to be a valid ID if the response time is less than 5 seconds after the SIS is powered up. The SIS will continually communicate a status message to the SDM. The SDM can reset the SIS by removing and applying power to it.

Conditions for Running the DTC

The SDM monitors the Left SIS loop with power on.

    • Left SIS will send an ID message to the SDM.
    • Left SIS will continuously send OK or NOK message to SDM.

Conditions for Setting the DTC

    • Ignition 1 Voltage is within normal operating voltage range
    • The SDM has received an ID message from the Left SIS which does not match the ID stored in the SDM memory.
    • When 2 Left SIS resets attempted without the correct identification detected.

Action Taken When the DTC Sets

The SDM commands ON the AIR BAG warning lamp via Class 2 serial data.

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

Check to ensure that the proper Left SIS is installed into vehicle.

Test Description

The following number refers to the step number in the diagnostic table:

  1. This test checks the communication status of the Left SIS.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform A Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Use the scan tool to request SIR DTCs display.

Does the scan tool indicate that this DTC is current?

Go to Step 3

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3

Replace the inflatable restraint side impact sensor (SIS) - Left. Refer to Inflatable Restraint Side Impact Sensor Replacement .

Did you complete the replacement?

Go to Step 4

--

4

  1. Use the scan tool in order to Clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the text.

Does the DTC reset?

Go to Step 2

System OK