XC70 AWD L6-3.2L VIN 98 B6324S (2009)
Communications Control Module: Description and Operation
Audio Module (AUD)
The most important task of the audio module (AUD) is handling the functions of the front, rear and center speakers.
The audio module (AUD) communicates with directly connected components and with other control modules and components via the MOST network, a
fiber optic network used for communication.
The audio module (AUD) checks executed activations and input/output signals via its integrated diagnostics. If the control module detects a fault, a
diagnostic trouble code is generated. Any diagnostic trouble codes are stored in the control module memory. The information can be read via the data
link connector in the vehicle.
In order to work correctly on the MOST network, the infotainment control module (ICM) checks that the serial number in the audio module (AUD) is
correct. The audio module (AUD) will not function if the number is incorrect. Try switching the ignition off and on if there are problems when replacing
the control module.
A simple way to check whether the control module is functioning is to switch on the radio and to then change the volume. The volume from the
loudspeakers should rise and fall with the changes.
The Audio module (AUD) is a slave module on the MOST network. The infotainment control module (ICM) is the master control module.
The following variants of the audio module (AUD) are available:
High Performance HP, headphone panel
Premium Sound HP, headphone panel
The number of functions and loudspeaker outlets varies between the versions. The power output of the versions is also different.
The control module is located under the right front seat.
For further information, also see Signal specifications.
The table below summarizes the input signals to and output signals from the audio module (AUD). The signal types are divided into directly connected
signals and MOST communication. The illustration below displays the same information with the Volvo component designations.