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.

The SDM inspects the wiring connection to the driver side air bag module by letting the perpetual current flow through the internal circuit and verify the resistance.

Conditions for Setting the DTC

The resistance of the driver side air bag deployment loop is higher than 3 ohms.

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

Visually inspect the connector and the wiring of the driver side air bag.

Is the connector disconnected?

--

Go to Step 2

Go to Step 3

2

Connect the connector and perform the Diagnostic System Check - SIR.

Has the Diagnostic System Check - SIR been performed?

--

Go to Step 3

Go to Diagnostic System Check - SIR

3

  1. Confirm the ignition switch is OFF.
  2. Disconnect the connector of the driver side air bag module.
  3. Disconnect the connector of the sensing and diagnostic module (SDM) wiring.
  4. Measure the resistance between terminal 37, 38 of the SDM and terminal 1, 2 of the driver side air bag module.

Is the resistance equal to the specified value?

0 ohms

Go to Step 5

Go to Step 4

4

Replace the air bag wiring.

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--

5

  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

6

Replace the driver side air bag module.

Is the replacement complete?

--

Go to Diagnostic System Check - SIR

--