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 Vehicle Diagnostic System Check before proceeding with these diagnostic procedures. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information.

Speakers - Distortion

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

With RPO UZ8 (Monsoon)

  1. Low level audio circuit open--Test the appropriate low level audio circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Defective speaker--Replace the appropriate speaker. Refer to Speaker Replacement Reference .

Important: The following procedure assumes all speakers are operative for all modes of operation except digital radio.

With RPO U2K

  1. Audio common circuit open or high resistance--Test the audio common circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Audio output from digital radio receiver--Replace the digital radio receiver. Refer to Control Module References in Computer/Integrating Systems.
  3. Digital radio output from the radio--Replace the radio. Refer to Control Module References in Computer/Integrating Systems.