Steering Column System

DTC B2815

DTC Descriptor

DTC B2815
Steering Wheel Controls Illegal Resistance Value

Diagnostic Fault Information
Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description
The body control module (BCM) supplies 12 volts 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
The BCM detects 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
^ The DTC will become history if the BCM no longer detects a circuit malfunction.
^ The history DTC will clear after 100 fault-free ignition cycles.
^ The DTC can be cleared with a scan tool.

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.
^ Review schematic when testing switch resistance values.

Reference Information

Schematic Reference

Steering Wheel Schematics

Connector End View Reference
^ Steering Wheel and Column Connector End Views
^ Computer/Integrating Systems Connector End Views

Electrical Information Reference
^ Circuit Testing
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs
^ Connector Repairs

Circuit/System Verification
Ignition ON, observe the scan tool steering wheel controls (SWC) Switch Voltage parameter in the body control module (BCM) data list . Pressing the switch should read voltage present, and drop to 0 volts when released.

Circuit/System Testing
It is recommended that Component Testing is performed before Circuit Testing when diagnosing steering wheel controls.

Caution: Refer to SIR Caution.

1. Ignition OFF, disconnect the right steering wheel control connector.
2. Ignition ON, with a scan tool, verify the SWC Switch Voltage parameter is at 0 volts.
^ If over 0 volts, test the remote radio control signal circuit for a short to voltage. If the circuits test normal, replace the BCM.
3. If all circuits test normal, refer to Component Testing.

Component Testing

Caution: Refer to SIR Caution.

1. Ignition OFF, disconnect the harness connector at the audio steering wheel control switches.
2. Test the switch for infinite resistance between the voltage supply terminal and the signal terminal with the switch in the open position.
^ If less than infinite resistance, replace the switch.
3. Test resistance values between the voltage supply terminal and the signal terminal with the switch closed in each position and verify readings are approximate to what the schematic reads.
^ If values do not, replace the switch.

Repair Instructions
Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
^ Steering Wheel Control Switch Assembly Replacement
^ Control Module References for BCM replacement, setup, and programming