Steering Wheel Controls Malfunction
Steering Wheel Controls Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
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.
Diagnostic Aids
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 (Steering Wheel Secondary/Configurable Control Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Steering Wheel Controls Description and Operation (Steering Wheel Controls Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool SWC Bank 1 status while pressing and releasing the switches. The reading should be SW1-SW10 identifying the switch pressed, and Idle 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.
• 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.
3. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminals listed below:
* Steering wheel control switch signal circuit terminal 6 - left switch
* Steering wheel control switch signal circuit terminal 2 - 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.
4. Ignition OFF, disconnect the X1 harness connector at the BCM.
5. Test for infinite resistance between ground and the signal circuit terminals listed below:
* Steering wheel control switch signal circuit terminal 6 - left switch
* Steering wheel control switch signal circuit terminal 2 - right switch
• If less than the specified value, test the signal circuits for a short to ground.
6. Ignition ON, test for less than 1 volt between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch.
• If greater than the specified range, test the voltage reference circuit for a short to voltage
7. Ignition ON, test for infinite resistance between ground and the voltage reference circuit terminal 5 at the left steering wheel control switch.
• If not the specified value, test the voltage reference circuit for a short to ground.
8. Test for less than 1 ohm between the voltage reference circuit terminal 5 at the left steering wheel control switch and the voltage reference circuit terminal 5 at the right steering wheel control switch.
• If greater than the specified range, test the voltage reference circuit for a an open/high resistance.
9. 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 5 and terminal 6 (left switch) or terminal 2 (right switch) of either the left or right steering wheel control switches.
• 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.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Steering Wheel Control Switch Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming