GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

Connector End Views Reference: Entertainment Connector End Views

Diagnostic System Check - Vehicle

Always perform the Radio/Audio System Diagnostic System Check before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information.

Important: The following information lists the most probable cause of the concern to the least probable cause, followed by the appropriate test for that condition. If the list leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Without RPO U2K or U42/U56

No audio output from the radio.

Test for any AC voltage between the left front audio signal circuits at the left front speaker connector with the radio volume adjusted to 50 percent. If no AC voltage is present, check for shorts to battery positive or shorts to ground on any speaker output circuit from the radio. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no shorts are located, replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

With RPO U2K or U42/U56

No audio output from the DVD player or Digital Radio Receiver (DRR).

Test for any AC voltage between the left or right audio signal circuits and audio common circuit at the radio connector. If no AC voltage is present, check for opens, shorts to battery positive or shorts to ground on left and right output circuit from the affected component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no shorts or opens are located, replace the affected component. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.