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.

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

Conditions for Setting the DTC

    • The side air bag wiring of the passenger high is shorted to battery wiring.
    • The side air bag wiring of the passenger 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?

--

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 passenger side air bag module.
  3. Disconnect the electrical connector at the SDM.
  4. Check the resistance between the SDM and the high, low wiring of passenger side 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 059 still shown as a current fault?

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Go to Step 6

System OK

6

Replace the passenger side air bag module.

Did you complete the repair?

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Go to Diagnostic System Check - SIR

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