GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2007 🢒 Rainier 🢒 DTC 🢒 DTC B1397 or B2815

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 B1397: Device Voltage Reference Output Circuit Low

DTC B2815: Steering Wheel Controls Illegal Resistance Value

Circuit/System Description

The body control module (BCM) supplies voltage to the audio steering wheel control multiple momentary contact switches and monitors the return signal. Each switch is associated to a set resistance value, when pressed a specific voltage drop occurs through a series of resistors unique to that switch. The BCM identifies the selection, then sends a serial data message that is received by the component controlled, activating the feature.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

B1397

The BCM senses a short to ground in the voltage circuit for more than 1 second.

B2815

The BCM senses a switch voltage that is higher than normal.

Action Taken When the DTC Sets

The BCM will ignore the switch command.

Conditions for Clearing the DTC
    • A current DTC clears when the malfunction is no longer present.
    • A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.

Diagnostic Aids
    • This diagnostic is for the audio steering wheel controls.
    • Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.

Reference Information

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

    •  Secondary/Configurable Control Connector End Views
    •  Data Communication Connector End Views

Description and Operation

Steering Wheel Controls Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Ignition ON, observe the scan tool Steering Wheel Controls (SWC) Switch Voltage parameter. Pressing the switch should read voltage present, and drop to 0 volts when released.

Circuit/System Testing

Important: It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Ignition ON, test for ignition voltage between the ignition circuit terminal 1 and ground.
    3. ⇒If less than the specified value, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  3. Test for 0 volts between the signal circuit terminal 6 and ground.
    4. ⇒If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
  4. Test for ignition voltage between the ignition circuit terminal 1 and the signal circuit terminal 6.
    5. ⇒If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
  5. Install a 3A fused jumper wire at the ignition circuit terminal 1 and the ignition circuit jumper terminal 2.
  6. Disconnect the harness connector at the left steering wheel control switch.
  7. Test for ignition voltage between the ignition circuit jumper terminal 1 and ground.
    8. ⇒If less than the specified value, test the ignition circuit jumper for a short to ground, or an open/high resistance.
  8. Test for ignition voltage between the ignition circuit jumper terminal 1 and the signal circuit terminal 5.
    9. ⇒If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the BCM.
  9. Disconnect the harness connector C1 at the BCM.
  10. Test for infinite resistance between the signal circuit terminal B8 and ground.
    11. ⇒If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  11. If all circuits test normal, test or replace the switch.

Component Testing

Caution: Refer to SIR Caution in the Preface section.

  1. Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
  2. Test for less than 2,400 ohms between the ignition circuit terminal 1 and the ignition circuit jumper terminal 2.
    3. ⇒If not the specified range, replace the steering wheel control switch.
  3. Test for infinite resistance between the ignition circuit terminal 1 and the signal terminal 6 with the switch in the open position.
    4. ⇒If not the specified range, replace the steering wheel control switch.
  4. Test for less than 2,400 ohms between the ignition circuit terminal 1 and the signal terminal 6 with the switch in the closed position.
    5. ⇒If greater than the specified range, replace the right steering wheel control switch.
  5. Disconnect the harness connector at the left steering wheel control switch.
  6. Test for infinite resistance between the ignition circuit jumper terminal 1 and the signal terminal 5 with the switch in the open position.
    7. ⇒If not the specified range, replace the steering wheel control switch.
  7. Test for less than 12,000 ohms between the signal terminal 5 and the ignition circuit jumper terminal 1 with the switch in the closed position.
    8. ⇒If greater than the specified range, replace the steering wheel control switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Steering Wheel Control Switch Assembly Replacement
    •  Control Module References for BCM replacement, setup, and programming