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 instrument panel module (IPM) supplies voltage to the 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 IPM identifies the selection, then sends a serial data message that is received by the component controlled, activating the feature. If equipped with adaptive cruise control the Gap+/Gap- switches are in place of the mute/source switches and are in the same resistor ladder circuit.

Diagnostic Aids

* Ensure the primary controls of the associated component are functioning properly before diagnosis of the steering wheel controls.
* Review schematic when testing switch resistance values.

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)

Circuit/System Verification

Ignition ON, observe the scan tool steering wheel controls counts while pressing the steering wheel control switch. The reading should change with each switch pressed and display counts when inactive.

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 IPM.

3. Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminal 4.

• If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.

4. Ignition OFF, disconnect the X3 harness connector at the IPM.
5. Test for infinite resistance between the signal circuit terminal 4 and ground.

• If less than the specified value, test the signal circuit 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 1 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 terminals 1 and 4 of either the left or right steering wheel control switch.

• If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the 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 IPM replacement, setup, and programming