Diagnostic Fault Information
Important: Always perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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 is performed before Circuit Testing when diagnosing steering wheel controls.
- Ignition OFF, disconnect the harness connector at the audio steering wheel control switch.
- Ignition ON, Radio ON, test for 8.5-10.5 volts between the 10-volt reference circuit and ground at the harness connector.
| ⇒ | If less than specified, test 10-volt reference circuit for short to ground or open/high resistance. If the circuit test is normal, replace the radio. |
| ⇒ | If greater than specified, test 10-volt reference circuit for short to ground or open/high resistance. If the circuit test is normal, replace the radio. |
- Test for less than 0.5 volts between the signal circuit and ground at the harness connector.
| ⇒ | If greater than specified, test the signal circuit for a short to voltage. If the circuit test is normal, replace the radio. |
- Test for 8.5-12 volts between the supply voltage circuit and the signal circuit at the harness connector.
| ⇒ | If less than 8.5 volts, test the signal circuit for an open/high resistance. If the circuit test is normal, replace the radio. |
- Ignition OFF, disconnect the harness connector at the radio.
- Test for infinite resistance between the signal circuit and ground at the harness connector.
| ⇒ | If less than infinite ohms of resistance, test the signal circuit for a short to ground. If the circuit test is normal, refer to component testing. |
- If all circuit test normal, refer to component testing.
Component Testing
Caution: Refer to SIR Caution in the Preface section.
- Ignition OFF, disconnect the harness connector at the audio steering wheel control switch.
- Test for infinite resistance between the 10-volt reference terminal and the signal terminal with the switch in the open position.
| ⇒ | If less than infinite resistance, replace the switch. |
- Test resistance values between the 10-volt reference 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
Important: Always perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
