The audio amplifier supplies 9 volts to the noise compensation microphone. The audio amplifier receives a signal from the noise compensation microphone to determine the amount of interior vehicle noise and adjusts the amplifier output to the speakers accordingly.

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

1. Ignition OFF, disconnect the harness connector at the noise compensation microphone.
2. Ignition ON, test for 8.5-9.5 volts between the noise compensation microphone supply voltage circuit terminal B and ground.

⇒	If less than the specified range, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the audio amplifier.

⇒	If greater than the specified range, test the voltage supply circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.

3. Ignition ON, test for 8.5-9.5 volts between the noise compensation microphone supply voltage circuit terminal B and the drain wire circuit terminal A.

⇒	If less than the specified range, test the drain wire circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the audio amplifier.

4. If all circuits test normal, replace the noise compensation microphone.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.