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
- 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. 
 
- Speaker output open. Test the appropriate speaker outputs for an open.
Refer to 
Circuit Testing 
 and 
Wiring Repairs 
 in Wiring Systems.
 
- Defective speaker. Replace the appropriate speaker. Refer to 
Speaker Replacement Reference 
 .
 
With RPO U56/U42 or U2K
- 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.
 
- Defective speaker. Replace the appropriate speaker. Refer to 
Speaker Replacement Reference 
 .
 
- 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.