Audio System - Popping Noises/Sound Drop-Out

91 08 105

2014972/3

November 11, 2008.

Supersedes Technical Service Bulletin Group 91 number 07-39 dated September 13, 2007 for reasons listed below.





Affected Vehicles

91 Popping sound and sound dropouts in all audio sources

Condition





After turning on the MMI system from bus sleep mode, popping sounds and sound dropouts occur in all audio sources (FM, AM, SAT, CD). No related fault codes are stored.

This condition may disappear after a few minutes of operation. It may happen more often in cold conditions.

Technical Background

The MP3-capable CD changer interrupts the communication on the MOST bus due to an internal component issue.

Tip:

Please refer to TSB 2014375, which addresses similar symptoms.

Production Solution

- Extended quality check at supplier on current CD changer.

- Introduction of improved parts.

Service

1. Verify condition. It may be necessary to switch the ignition off, lock the vehicle and wait for bus sleep mode.

2. If verified, loop the optical bus of the MP3-capable CD changer, switch the system off and wait for bus sleep mode.

3. Switch the MMI system on again. If sound quality is now flawless, replace the MP3-capable CD changer.

4. If problem persists, open a TAC ticket for further assistance. Make sure to attach the diagnostic log.





Warranty





Required Parts and Tools

Additional Information

All parts and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Department and service manuals for the latest information.