GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The seat belt pretensioner deployment loop consists of a seat belt pretensioner, the seat belt pretensioner high and seat belt pretensioner low circuits. A shorting bar is used in the seat belt pretensioner connector which will short together the seat belt pretensioner high and seat belt pretensioner low circuits when the connector is disconnected, this will help to prevent unwanted deployment of the seat belt pretensioner during servicing. During a frontal crash of sufficient force the sensing and diagnostic module (SDM) will allow current to flow through the deployment loop in order to deploy the seat belt pretensioner. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. If a malfunction is detected, a DTC will be stored.

Conditions for Running the DTC

Ignition voltage is within the normal operating voltage range.

Conditions for Setting the DTC

    • DTC 65 will set when the SDM detects a short to voltage in the RH seat belt pretensioner deployment loop.
    • DTC 66 will set when the SDM detects a short to ground in the RH seat belt pretensioner deployment loop.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • A short to voltage in the seat belt pretensioner high or the seat belt pretensioner low circuits
    • A short to ground in the seat belt pretensioner high or the seat belt pretensioner low circuits
    • A malfunctioning RH seat belt pretensioner
    • An internal SDM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Test the seat belt pretensioner high and the seat belt pretensioner low circuits for a short to voltage.

  2. Test to see if the malfunction is caused by the RH seat belt pretensioner.

  3. Test the seat belt pretensioner high and the seat belt pretensioner low circuits for a short to ground.

Step

Action

Value(s)

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform a Diagnostic System Check - SIR?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2

Is DTC 65 or 66 set as a current DTC?

--

Go to Step 3

Go to Diagnostic Aids

3

Is DTC 65 set as a current DTC?

--

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the seat belt pretensioner connector.
  3. Disconnect the sensing and diagnostic module (SDM) connector.
  4. Test the seat belt pretensioner high and the seat belt pretensioner low circuits for a short to voltage using EL-46863 Test Leads. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

5

Is DTC 66 set as a current DTC?

--

Go to Step 6

--

6

Use the scan tool to display the RH Pretensioner deployment loop resistance.

Does the resistance display within the specified range?

Approximately 1.6-6.4 ohms

Go to Step 7

Go to Step 8

7

  1. Use the scan tool in order to Clear the DTCs.
  2. Use the scan tool in order to Read the DTCs.
  3. Wiggle the wiring harness between the SDM and the seat belt pretensioner while observing the scan tool.

Did the DTC status change from NO DTCs?

--

Go to Step 10

Go to Step 13

8

  1. Turn OFF the ignition.
  2. Install EL-46841 SIR Pretensioner Load Tool to the seat belt pretensioner harness connector.
  3. Connect the battery. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  4. Use the scan tool to display the RH pretensioner deployment loop resistance.

Does the resistance display as specified?

Approximately 3.0 ohms

Go to Step 11

Go to Step 9

9

  1. Disconnect the SDM connector.
  2. Test the seat belt pretensioner high and the seat belt pretensioner low circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

10

Locate and repair intermittent short to ground in wiring harness. Refer to Testing for Intermittent Conditions and Poor Connections , Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

--

11

Replace the RH seat belt pretensioner. Refer to Seat Belt Buckle Pretensioner Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

  1. Reconnect all SIR components.
  2. Verify that all components, connectors and CPAs are properly mounted.
  3. Use the scan tool in order to Clear the DTCs.
  4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK