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

Without RPO U56/U42 or U2K

  1. No audio output from the radio. Test for any AC voltage between the audio signal circuits at the affected speaker connector with the radio volume adjusted to 50 percent. If no AC voltage is present, check for shorts to battery positive voltage or shorts to ground on all affected speaker output circuits from the radio. If no shorts are located, replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.
  2. Speaker output open. Test the appropriate speaker outputs for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  3. Defective speaker. Replace the appropriate speaker. Refer to Speaker Replacement Reference .

With RPO U56/U42 or U2K

  1. Remote Playback Device Audio Circuit open, shorted to ground or shorted to battery positive. Test the appropriate remote playback device audio circuit for an open, short to ground or short to battery positive, Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
  2. Defective speaker. Replace the appropriate speaker. Refer to Speaker Replacement Reference .
  3. No audio output from the radio. Test for any AC voltage between the audio signal circuits at the affected speaker connector with the radio volume adjusted to 50 percent. If no AC voltage is present, check for shorts to battery positive voltage or shorts to ground on all affected speaker output circuits from the radio. If no shorts are located, replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.