Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

The radio supplies 10 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 radio will perform the desired function, or send a serial data message to another component.

Schematic Reference

Steering Wheel Schematics

Connector End View Reference

Electrical Information Reference

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, Radio ON, test for 9.2-10 volts between the 10-volt reference circuit and ground at the right switch harness connector.

⇒	If less than 9.2 volts, test 10-volt reference circuit for short to ground or open/high resistance. If circuit test normal, replace radio.

⇒	If greater than 10 volts, test the 10-volt reference circuit for short to voltage. If circuit test normal, replace radio.

3. Connect a 3-amp fused jumper wire between the 10-volt reference circuit and the signal circuit, verify that DTC B3608 sets.

⇒	If DTC B3608 does not set, test the signal circuit for a short to ground or an open/high resistance. If circuit test normal, replace the radio.

4. If all circuits test normal, refer to component testing.

Caution: Refer to SIR Caution in the Preface section.

1. Ignition OFF, disconnect the harness connector at the suspect audio steering wheel control switch.
2. Test for infinite resistance between the supply voltage 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 supply voltage 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.

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.