Circuit/System Description

WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

Each of the audio output channel circuits (+) and (-), at the radio and at the amplifier have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5 V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1 V AC and less, where constant music may measure 3 V AC and slightly higher.

Amplifier UQA

The radio provides left and right audio signals to the amplifier. The amplifier is supplied battery voltage from a dedicated fuse in the rear fuse block. The amplifier communicates with the vehicle via serial data, which controls the power state of the amplifier and allows the amplifier to set DTCs. Balance/fade and muting functions are all performed by the amplifier based on serial data messages.

Amplifier UQ3

The radio provides four channels of audio signals to the amplifier- left front, left rear, right front and right rear. The amplifier is supplied battery voltage from a dedicated fuse in the rear fuse block. The amplifier power state is controlled by a remote enable signal via the antenna 14V switched supply circuit, which also provides power to the antenna module. Amplifier muting functions are controlled by a dedicated pulse width modulated signal from the radio via the amp control circuit. The amplifier provides eight audio output channels to the speakers. This amplifier does not communicate on the serial data bus and cannot set DTCs.