For 1990-2009 cars

Step | Action | Value | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Radio/Navigation System Schematics Connector End View Reference: Entertainment/Communication Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn the ignition to ON with the engine running.
2. Turn ON the blower motor on the maximum speed.
3. Cycle the auto volume control ON and then OFF.

Is a difference in volume heard?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3 |

1. Engine off, ignition on.
2. Disconnect the noise compensation microphone.
3. Measure the voltage from the noise compensation microphone supply voltage circuit to the drain wire.

Is the voltage measured near the specified value?

8 V

Go to Step 4

Go to Step 5

4 | Replace the noise compensation microphone. Refer to Radio Volume Compensator Interior Noise Microphone Replacement. Is the replacement complete? | -- | Go to Step 9 | --
5 | Test the noise compensation microphone supply voltage circuit for an open or short. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6
6 | Test the drain wire circuit for an open or short. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7
7 | Inspect for poor connections at the amplifier. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8
8 | Replace the amplifier. Refer to Control Module References for replacement, setup, and programming. Is the repair complete? | -- | Go to Step 9 | --
9 | Operate the system in order to verify the repair. Is the failure removed? | -- | System OK | Go to Step 3