GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 Savana 🢒 DTC 🢒 DTC B0064, B0065, or B0066

Circuit Description

The inflatable restraint seat belt pretensioner-LF deployment loop consists of a seat belt pretensioner, seat belt pretensioner high control circuit, and seat belt pretensioner low control circuit. A shorting bar is used within the seat belt pretensioner connector which will short together the seat belt pretensioner high and seat belt pretensioner low control circuits when the connector is disconnected. This will help to prevent unwanted deployment of the pretensioner during servicing. When the ignition is turned ON, the inflatable restraint sensing and diagnostic module (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 diagnostic trouble code (DTC) will be stored in memory.

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC
    • DTC B0064 will set when the SDM detects the seat belt pretensioner-LF deployment loop resistance is less than 1.3 ohms for 500 milliseconds.
    • DTC B0065 will set when one of the following conditions occurs:
       - The SDM detects the seat belt pretensioner-LF high control is less than 2.4 volts and seat belt pretensioner-LF deployment loop resistance is 6 ohms or greater for 500 milliseconds.
       - The SDM detects the seat belt pretensioner-LF deployment loop resistance is greater than 4.8 ohms for 500 milliseconds.
    • DTC B0066 when one of the following conditions occur:
       - The SDM detects the seat belt pretensioner-LF high control is greater than 6 volts for 500 milliseconds.
       - The SDM detects the seat belt pretensioner-LF high control is less than 2.4 volts and seat belt pretensioner-LF deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets

The SDM commands the AIR BAG indicator ON via Class 2 serial data.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 255 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following can cause an intermittent condition:

    • A short between the seat belt pretensioner-LF high and low control circuits
    • An open or a high resistance in the seat belt pretensioner-LF high or low control circuits
    • A malfunctioning shorting bar on the seat belt pretensioner-LF connector

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. Inspects the seat belt pretensioner-LF in-line connector.

  2. Tests for a malfunctioning seat belt pretensioner-LF.

    3.

  3. Tests for current DTCs. If DTC B0064 is present, test for a short between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits. If DTC B0065 is present, test for an open or high resistance between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits. If DTC B0066 is present, test for a short to ground or voltage between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views

1

Did you perform the Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Disconnect the seat belt pretensioner-LF in-line connector. Refer to Seat Belt Buckle Pretensioner Replacement .
  3. Inspect both halves of the connector for the following conditions:
    4. • Corrosion
    • Terminal damage
    • Poor connections/terminal tension

Do the connectors exhibit any signs of corrosion, terminal damage, or poor connections?

Go to Step 3

Go to Step 4

3
  1. If the seat belt pretensioner-LF in-line connector exhibits any of the above conditions, the pretensioner must be replaced. Refer to Seat Belt Buckle Pretensioner Replacement .
  2. Replace the harness side of the seat belt pretensioner-LF in-line connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 9

--

4

  1. Connect the J 38715-A SIR Load Tool to the harness side of the seat belt pretensioner-LF in-line connector.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, request the SIR DTC display.

Does the scan tool indicate that either DTC B0064, B0065, or B0066 is current?

Go to Step 5

Go to Step 8

5
  1. Turn OFF the ignition.
  2. Remove the J 38715-A .
  3. Disconnect the SDM connector. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  4. Inspect the SDM connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

    • If DTC B0064 is present, test for a short between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
    • If DTC B0065 is present, test for an open or high resistance between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
    • If DTC B0066 is present, test for a short to ground or voltage between the seat belt pretensioner-LF high and seat belt pretensioner-LF low control circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

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

Did you complete the replacement?

Go to Step 9

--

8

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

Did you complete the replacement?

Go to Step 9

--

9
  1. Reconnect all SIR system 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