Diagnostic Instructions
Circuit/System Description
The radio supplies voltage to the audio steering wheel control 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 then identifies the selection to activate the feature, otherwise sends a serial data message received by the controlled component activating the feature.
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. |
| • | If a single switch function is inoperative, test the suspect switch. Refer to component testing. |
Reference Information
Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics
Connector End View Reference
Description and Operation
Steering Wheel Controls Description and Operation
Electrical Information Reference
Circuit/System Testing
Caution: Refer to SIR Caution in the Preface section.
Important: It is recommended that Component Testing be performed before Circuit Testing, when diagnosing steering wheel controls.
- Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
- Ignition ON, radio ON, test for 8.5-10.5 volts between the 10-volt reference circuit terminal 2 and ground.
| ⇒ | If less than the specified value, test the 10-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If greater than the specified value, test the
10-volt reference circuit for a short to voltage. If the circuit tests normal, replace the radio. |
- Test for 8.5-10.5 volts between the 10-volt reference circuit and the signal circuit terminal 1.
| ⇒ | If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If greater than the specified value, test the signal circuit for a short to
voltage. If the circuit tests normal, replace the radio. |
- Ignition OFF, disconnect the harness connector C2 at the radio.
- Test for infinite resistance between the signal circuit terminal 11 and ground.
| ⇒ | If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the switch. |
- If all circuits test normal, test or replace the switch.
Component Testing
Caution: Refer to SIR Caution in the Preface section.
- Ignition OFF, disconnect the harness connector at the right steering wheel control switch.
- Test for infinite resistance between the signal terminal 1 and the 10-volt reference terminal 2 with the switch in the open position.
| ⇒ | If not the specified value, replace the switch. |
- Test the resistance values between the signal terminal 1 and the 10-volt reference terminal 2 with the switch closed in each position, and verify are approximate to what the schematic reads.
| ⇒ | If values do not match, replace the switch. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
