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.

Upon passing this test, ignition and deployment loop voltages are measured to ensure they are within the 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.

Conditions for Setting the DTC

    • The side air bag wiring of the driver high is shorted to battery wiring.
    • The side air bag wiring of the driver low is shorted to battery wiring.

Step

Action

Values

Yes

No

Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section.

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

 

1

Did you perform the Diagnostic System Check - SIR?

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Go to Step 2

Go to Diagnostic System Check - SIR

2

Visually inspect the supplemental inflatable restraints (SIR) wiring harness.

Is there any visible damage to the SIR wiring harness?

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Go to Step 3

Go to Step 4

3

Replace the SIR wiring harness.

Did you complete the repair?

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Go to Diagnostic System Check - SIR

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4

  1. Turn OFF the ignition.
  2. Disconnect the electrical connector for the driver air bag module.
  3. Disconnect the electrical connector at the SDM.
  4. Check the resistance between the SDM and the high, low wiring of driver air bag module and the battery.

Is the resistance as specified?

10k ohms

Go to Step 5

Go to Step 3

5

  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement.
  2. Turn ON the ignition.
  3. Using the scan tool, Clear DTCs.
  4. Perform Diagnostic System Check - SIR.

Is DTC 055 still shown as a current fault?

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Go to Step 6

System OK

6

Replace the driver side air bag module. Refer to Inflatable Restraint Steering Wheel Module Replacement .

Did you complete the repair?

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Go to Diagnostic System Check - SIR

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