GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.

These test ignition and deployment loop voltages are measured to ensure that they are within their normal voltage ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deploy loops.

Each seat belt switch is cyclic monitored. The time of the buckle status change is 2 seconds. When the SDM cannot define the buckle status for 25 cycles, the SDM recognizes that the buckle is not stable and generates a buckle status settle fault.

Conditions for Setting the DTC

The driver seat belt switch wiring is opened or shorted to battery wiring.

Step

Action

Values

Yes

No

Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section.

Caution: Refer to SRS Sensing and Diagnostic Module Handling Caution in the Preface section.

 

1

  1. Confirm the ignition switch is OFF and the sensing and diagnostic module (SDM) fuse has been removed.
  2. Wait for 1 minute to discharge the SDM charger.

Has the SDM discharged?

--

Go to Step 2

--

2

Visually inspect the connector and the wiring of the driver seat belt switch.

Is the driver seat belt switch wiring damaged?

--

Go to Step 5

Go to Step 3

3

  1. Confirm the ignition switch is OFF.
  2. Disconnect the connector of the driver seat belt switch wiring.
  3. Disconnect the connector of the SDM wiring.
  4. Measure the resistance between the terminal 1, 2 of the driver seat belt switch and the battery.

Is the resistance equal to the specified value?

10 K ohms

Go to Step 4

Go to Step 5

4

  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Confirm the ignition switch is ON.
  3. Erase the DTC using the scan tool.
  4. Perform the Diagnostic System Check-SIR.

Is the DTC removed?

--

Go to Diagnostic System Check - SIR

Go to Step 6

5

Replace the air bag wiring.

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--

6

Replace the driver buckle assembly.

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

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