GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Rear Audio Left Signal

1

1

2

--

Rear Audio Right Signal

1

1

2

--

Rear Audio Common Signal

--

2

2

--

1. Loss of audio channel during mobile entertainment system play.

2. Degraded audio playback during mobile entertainment system play.

Circuit/System Description

The rear audio signals and rear audio common circuits are outputs from the mobile entertainment player module. These circuits carry the mobile entertainment audio signals to the disc player and video display.

Diagnostic Aids

This diagnostic assumes that the audio quality is good while playing a DVD or during play of an auxiliary audio source through the mobile entertainment system. This diagnostic also assumes that the audio quality is poor or non-existent only during mobile entertainment system play. Be sure to check for these conditions. Be sure that there is an audio selection available to play via the mobile entertainment cartridge.

Reference Information

Schematic Reference

Video System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

  1. Ignition ON.
  2. Turn the radio ON. Select the mobile entertainment system as the source.
  3. Play a selection on the mobile entertainment system.

Circuit/System Testing

  1. Ignition OFF. Disconnect the mobile entertainment player module. Test for continuity in the right and left audio circuits through the audio coupling transformer.
  2. If there is no continuity through the audio coupling transformer, replace the harness.
  3. Test the rear audio signals for a short to ground or short to voltage.
  4. Test the rear audio common circuit for an open or short to voltage.
  5. Disconnect the disk player and video display . Test for continuity in the right and left audio circuits through the audio coupling transformer.
  6. If there is no continuity through the audio coupling transformer, replace the harness.
  7. Test the rear audio signals for a short to ground or short to voltage.
  8. Test the rear audio common circuit for an open or short to voltage.
  9. If the circuits test normal, test or replace the mobile entertainment player module.
  10. If all circuits test normal, test or replace the disk player and video display .

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Mobile Entertainment Data Cartridge Access Lower Door Replacement
    •  Video Disc Player Replacement