GM Service Manual Online
For 1990-2009 cars only

Schematic Reference: Radio/Audio System Schematics

Connector End View Reference: Entertainment Connector End Views

Diagnostic System Check - Vehicle

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

Voice Guidance Inoperative or Degraded

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.

  1. Audio Prompt Out Circuits open or shorted--Test the Audio Prompt Out circuits for an open, short to ground or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Defective Radio--Replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  3. Defective Amplifier--Replace the amplifier. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.