Test I: The Audio Volume Cutback Command Is Inoperative

PINPOINT TEST I: THE AUDIO VOLUME CUTBACK COMMAND IS INOPERATIVE

Normal Operation
With the ignition switch in the RUN position and the gear selector in REVERSE (R), the parking aid system calculates the distance to an object by the use of a radar sensor. A 750 Hz variable warning tone is generated by the parking aid sounder. A volume cutback request message is sent to the audio unit from parking aid module (PAM) over the medium speed controller area network (MS-CAN) to decrease the volume of the audio unit. The sounder increases its warning tone rate as the vehicle gets closer to an obstacle. When an object is detected within 46 cm (18 in) of the vehicle, the warning tone becomes continuous.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- PAM
- Audio Unit

I1:

I2-I3: