GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2009 🢒 Ascender - 4WD 🢒 DTC 🢒 DTC B0061, B0062, or B0068

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 B0061: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Resistance Low

DTC B0062: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Open

DTC B0068: Left Front/Driver Roof Rail/Head Curtain Bag Deployment Loop Voltage Out of Range

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Roof Rail Module - Left High

B0068

B0068

B0062

B0068

B0061

Roof Rail Module - Left Low

B0068

B0068

B0062

B0068

B0061

Circuit/System Description

The driver roof rail deployment loop consists of an inflatable restraint roof rail module - left and the roof rail module high and low circuits. A shorting bar used within the roof rail module connector shorts together both the roof rail module high and low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the inflator module during servicing. During a side or 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 roof rail module. 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 in memory.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

B0061

The DTC will set when the roof rail module - left deployment loop resistance is less than 1.3 ohms for 500 milliseconds.

B0062

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

    • Roof rail module - left high circuit is less than 2.4 volts and the roof rail module - left deployment loop is more than 6 ohms for 500 milliseconds.
    • Roof rail module - left deployment loop resistance is more than 4.8 ohms for 500 milliseconds.

B0068

This DTC will set when one of the following conditions occur:

    • Roof rail module - left high or low circuit is shorted to ground or short to voltage for 500 milliseconds.
    • Roof rail module - left high circuit is less than 2.4 volts and roof rail module - left deployment loop resistance is less than 6 ohms for 500 milliseconds.

Action Taken When the DTC Sets
    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
    • 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.
    • A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Special Tools

    • J 38715-A SIR Driver/Passenger Load Tool
    • J 38715-30A Load Tool Adapter

Circuit/System Testing

Important: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.

   • Left roof rail module
   • SDM
   • Left roof rail module wiring harness connector
   • SDM wiring harness connector

  1. Ignition OFF, disconnect harness connector at the left roof rail module.
  2. Use J 38715-30A to connect the J 38715-A to the harness side of the left roof rail module. Use the PASSENGER INFLATOR connector located on the load tool.
  3. Ignition ON, verify B0061, B0062, or B0068 is set current.
    4. ⇒If B0051, B0052, or B0068 is history replace the left roof rail module.
  4. Ignition OFF, disconnect and remove the J 38715-A .
  5. Disconnect the harness connector at the SDM.
  6. Test for infinite resistance between the left roof rail module control circuit terminal A and ground.
    7. ⇒If less than the specified value, test the circuit for a short to ground.
  7. Test for infinite resistance between the left roof rail module control circuit terminal B and ground.
    8. ⇒If less than the specified value, test the circuit for a short to ground.
  8. Ignition ON, test for less than 1 volt between the left roof rail module control circuit terminal A and ground.
    9. ⇒If greater than the specified range, test the control circuit for a short to voltage.
  9. Test for less than 1 volt between the left roof rail module control circuit terminal B and ground.
    10. ⇒If greater than the specified range, test the control circuit for a short to voltage.
  10. Ignition OFF, test for less then 1 ohm between the left roof rail module terminal A and SDM signal circuit terminal 13.
    11. ⇒If greater than the specified range, test the circuit for an open/high resistance.
  11. Test for less then 1 ohm between the left roof rail module terminal B and SDM voltage circuit terminal 12.
    12. ⇒If greater than the specified range, test the circuit for an open/high resistance.
  12. If all circuits test normal, replace the SDM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  SIR/SRS Wiring Repairs
    •  Inflatable Restraint Roof Side Rail Module Replacement - Front
    •  Control Module References for SDM replacement, setup, and programming