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 B1397: Device Voltage Reference Output Circuit Low

DTC B2815: Steering Wheel Controls Illegal Resistance Value

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+ Voltage Reference

B1397

1

--

B2815

Steering Wheel Control Switch Signal

1

1

1

--

1. Steering Wheel Controls Inoperative

Circuit/System Description

The body control module (BCM) supplies voltage to the audio steering wheel control switches and monitors the return signal. Each switch state is associated to a set resistance value and when pressed a specific voltage drop occurs across the resistor unique to the switch. The BCM identifies the switch selection and activates the feature.

Conditions for Running the DTC

    • Battery voltage is between 9-16 volts
    • 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 switch inputs.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear once 100 consecutive malfunction free ignition cycles have occurred.

Reference Information

Schematic Reference

Steering Wheel Secondary/Configurable Control Schematics

Connector End View Reference

Component 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

Control Module References for Scan Tool Information

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

  1. Ignition OFF, disconnect the harness connector at the left and right steering wheel control switches.
  2. Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground.
  3. If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  4. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminals listed below:
  5. • Steering wheel control switch signal circuit terminal 5 - left switch.
    • Steering wheel control switch signal circuit terminal 6 - right switch.
    If less than the specified value, test the signal circuits for a short to voltage or an open/high resistance. If the circuits test normal, replace the BCM.
  6. Ignition OFF, disconnect the X1 harness connector at the BCM.
  7. Test for infinite resistance between ground and the signal circuit terminals listed below:
  8. • Steering wheel control switch signal circuit terminal 5 - left switch.
    • Steering wheel control switch signal circuit terminal 6 - right switch.
    If less than the specified value, test the signal circuits for a short to ground.
  9. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 1 at the left steering wheel control switch.
  10. If greater than the specified range, test the voltage reference circuit for a short to voltage
  11. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 1 at the left steering wheel control switch.
  12. If not the specified value, test the voltage reference circuit for a short to ground.
  13. Test for less than 1 ohm between the voltage reference circuit terminal 1 at the left steering wheel control switch and the voltage reference circuit terminal 2 at the right steering wheel control switch.
  14. If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
  15. If all circuits test normal, test or replace the left or right steering wheel control switch.

Component Testing

  1. Disconnect the harness connector at the right or left steering wheel control switch.
  2. Connect a DMM between terminal 1 and terminal 5 (left switch) or terminal 6 (right switch) of either the left or right steering wheel control switches.
  3. If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the left or right steering wheel control switch.

Left Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Mute/Voice Recognition

615 Ohms

815 Ohms

Program

1.7k Ohms

2.1k Ohms

Source Down

4.1k Ohms

4.5k Ohms

Source Up

11.0k Ohms

11.4k Ohms

No Switch Pressed

O.L.

O.L.


Right Steering Wheel Switch Resistance

Function Switch

Minimum Resistance Value

Maximum Resistance Value

Volume Up

1.1k Ohms

1.3k Ohms

Volume Down

1.4k Ohms

1.8k Ohms

Seek Up

1.7k Ohms

2.1k Ohms

Seek Down

2.2k Ohms

2.6k Ohms

No Switch Pressed

O.L.

O.L.

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