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 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 passenger air bag module by letting the infinitesimal current flow through the internal circuit and verify the resistance.

Conditions for Setting the DTC

The resistance of the passenger belt pretensioner deploy loop is over 3.1 ohms.

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

Perform the Diagnostic System Check - SIR.

Did you perform the Diagnostic System Check - SIR?

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Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Disconnect the negative battery cable.
  2. Wait 1 minute for the sensing and diagnostic module (SDM) capacitor to discharge.
  3. Examine the wiring and the connector at the passenger seat belt pretensioner module.

Is the connector disconnected?

--

Go to Step 3

Go to Step 4

3

  1. Reconnect the passenger seat belt pretensioner module connector.
  2. Reconnect the negative battery cable.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

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4

  1. Disconnect the electrical connector for the passenger seat belt pretensioner module.
  2. Disconnect the electrical connector at the SDM.
  3. The shorting bar at the disconnected SDM connector will create a complete circuit between the wires from the passenger seat belt pretensioner module.

  4. Connect an ohmmeter to the terminals on the SDM side of the wiring harness connector for the passenger seat belt pretensioner module.

Does the ohmmeter show the specified value?

0 ohms

Go to Step 5

Go to Step 7

5

  1. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  2. Reconnect the negative battery cable.
  3. Set the scan tool to CODE ERASE.
  4. Perform the Diagnostic System Check - SIR.

Is DTC 013 still shown as a current fault?

--

Go to Step 6

System OK

6

  1. Replace the passenger seat belt pretensioner module. Refer to Front Seat Belt Replacement in Seat Belts.
  2. Reconnect the negative battery cable.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

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7

  1. Replace the supplemental inflatable restraints (SIR) wiring harness.
  2. Reconnect the negative battery cable.

Did you complete the repair?

--

Go to Diagnostic System Check - SIR

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