GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0064: Left Front/Driver Pretensioner Deployment Loop Resistance Low

DTC B0065: Left Front/Driver Pretensioner Deployment Loop Open

DTC B0066: Left Front/Driver Pretensioner Deployment Loop Voltage Out of Range

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Seat Belt Pretensioner - LF High Circuit

B0066

B0066

B0065

B0066

B0064

Seat Belt Pretensioner - LF Low Circuit

B0066

B0066

B0065

B0066

B0064

Circuit/System Description

The driver seat belt pretensioner deployment loop consists of a seat belt pretensioner - LF and the seat belt pretensioner - LF high and low circuits. A shorting bar used within the seat belt pretensioner connector shorts together both the seat belt pretensioner high and low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the pretensioner during servicing. During a frontal crash of sufficient force the inflatable restraint 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 diagnostic trouble code (DTC) will be stored in memory.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0064

DTC B0064 will set when the seat belt pretensioner - LF deployment loop resistance is less than 1.3 ohms for 500 milliseconds.

B0065

DTC B0065 will set when one of the following conditions occurs:

    • Seat belt pretensioner - LF high circuit is less than 2.4 volts and the seat belt pretensioner - LF deployment loop is more than 6 ohms for 500 milliseconds.
    • Seat belt pretensioner - LF deployment loop resistance is more than 4.8 ohms for 500 milliseconds.

B0066

DTC B0066 when one of the following conditions occur:

    • Seat belt pretensioner - LF high or low circuits is short to ground or short to voltage for 500 milliseconds.
    • Seat belt pretensioner - LF high circuit 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.
    • The SIR system is disabled and no deployments are allowed.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists and the scan tool Clear DTC function is used.
    • A history DTC will clear once 255 malfunction-free ignition cycles have occurred.

Diagnostic Aids

If there is more than one DTC set diagnose the open DTC first. The following are possible causes of the malfunction:

    • A short between the seat belt pretensioner - LF high and low circuits
    • An open or a high resistance in the seat belt pretensioner - LF high or low circuits
    • A short to ground or a short to voltage in the seat belt pretensioner - LF high or low circuits
    • The seat belt pretensioner - LF connector
    • The SDM connector
    • A malfunctioning seat belt pretensioner
    • A malfunctioning SDM

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

SIR Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Special Tools

    • J 38715-A SIR Driver/Passenger Load Tool
    • J 38715-50 Load Tool Adapter

Circuit/System Testing

  1. With the ignition OFF, disconnect seat belt pretensioner connector.
  2. Inspect the component and wiring harness sides of connector for the seat belt pretensioner for damage or corrosion.
  3. If the connector for the seat belt pretensioner is damaged, the seat belt pretensioner must be replaced.
    If the seat belt pretensioner wiring harness side connector is damaged, replace the connector.
  4. Use J 38715-50 adapter to connect the J 38715-A SIR Driver/Passenger Load Tool to the harness side of the seat belt pretensioner wiring harness connector. Use the PASSENGER INFLATOR connector located on the load tool.
  5. With the ignition ON, use a scan tool to observe the SIR DTC display. Verify DTC B0064, B0065, or B0066 are set in history.
  6. If DTC B0064, B0065, or B0066 is history replace the seat belt pretensioner.
  7. With the ignition OFF, disconnect and remove the J 38715-A and adapter.
  8. Remove the inflatable restraint sensing and diagnostic module (SDM) connector. Inspect the SDM connector for damage or corrosion that may cause a malfunction in the seat belt pretensioner high and/or low circuits.
  9. If damage or corrosion is found make the appropriate repair.
  10. Test the high and low circuits between the SDM and seat belt pretensioner for a short to voltage, short to ground, or open/low resistance.
  11. If circuits test good then replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Seat Belt Retractor Pretensioner Replacement - Front
    •  SIR/SRS Wiring Repairs
    •  Control Module References for SDM replacement, setup, and programming