Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Diagnose and repair any serial data communication DTCs before performing this diagnostic.

Without Amplifier

Ignition ON and radio ON, adjust the volume, balance and fade adjustment on the radio.
- If adjustment of the fade and balance eliminates the concern, review the operation of the radio with the customer.
If inoperative audio on all speakers persists, replace the radio.

With Amplifier

Ignition ON and radio ON, adjust the volume, balance and fade adjustment on the radio.
- If adjustment of the fade and balance eliminates the concern, review the operation of the radio with the customer.
Ignition OFF, disconnect the X3 (U87) or X1 (UQ3) amplifier harness connector.
Ignition ON and radio ON, test for AC voltage between the left front low level audio signal (+) terminal 1 (U87) or 15 (UQ3) and left front low level audio signal (-) terminal 8 (U87) or 7 (UQ3).
- If AC voltage is not present, replace the radio.
Test for greater than 9 volts at the amplifier harness connector radio audio mute signal circuit, X3 terminal 7 (U87), X1 terminal 11 (UQ3).
- If less than specified value repair short to ground or open/high resistance or replace the radio.
Ignition OFF, disconnect the amplifier connector harness X1.
Test for less than 1 ohm between the X3 amplifier harness connector terminal 8 and ground.
- If greater than specified value repair open circuit.
Test for greater than 10 volts on X3 amplifier harness connector terminal 4.
- If less than specified value repair short to ground or open/high resistance.
If all circuits test normal, replace the amplifier.