Technical Service Bulletin
91 Audio system does not recognize or cannot play music files from SD Card
91 14 24 2020399/2 January 24, 2014. Supersedes Technical Service Bulletin Group 91 number 09-30 dated April
14, 2009 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

A4

2009-2015

All

Not Applicable

A5

2008-2015

All

Not Applicable

A5 Cabriolet

2010-2015

All

Not Applicable

A6

2005-2015

All

Not Applicable

A7

2011-2015

All

Not Applicable

A8

2005-2009

All

Not Applicable

Q5

2009-2015

All

Not Applicable

Q7

2007-2015

All

Not Applicable

Condition
REVISION HISTORY
Revision

Date

Purpose

2

-

Revised header data (Added model years)
Revised entire bulletin for clarity

1

04/14/2009

Initial publication

The Audi MMI system will not play audio files from an SD card. One of the following scenarios is present:
• Scenario A: The MMI system does not
recognize the audio files on the SD card.
• Scenario B: The MMI system reports that
the audio files on the SD card are
damaged (Figure 1).
• Scenario C: The audio files on the SD
card will play on one Audi vehicle, but will
not play on a different Audi vehicle.

Figure 1. Damaged audio file message.

© 2014 Audi of America, Inc.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of
Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior
expressed written permission of the publisher.

Technical Service Bulletin
Technical Background
For Scenario A and Scenario B:
Scenario A or Scenario B can result from one of the three following causes:
• The file type of the audio file is not supported by the Audi MMI system.
Typically, the Audi MMI system supports the following formats (when discussing supported files formats with
the customer, refer to the vehicle owner’s manual):
• .mp3
• .wav
• .wma
• .m4a (Copyright-protected DRM files are not supported.)
• .m4b (Copyright-protected DRM files are not supported. Bookmarks are not supported.)
• .mp4 (Audio files only. Audio files encoded with Apple Lossless encoding are not supported.)
If the file type of the audio file on the SD card is not listed above, the file will not play in the MMI system.
Some model year 2004 - 2009 owner’s manuals incorrectly described the .aac file extension as
compatible. Some AAC-encoded files are compatible, but files with the .aac extension are not. This error was
corrected with model year 2010 owner’s manuals.
• The customer added the audio files to the SD card using iTunes
on a Mac OS computer, and the vehicle has the base Concert
radio system.
The SD card has FAT formatting, which is the only type of formatting
supported by the Audi MMI system. FAT formatting is not traditionally
used by Mac OS, and as a result, Mac OS adds hidden files (Figure 2)
to the SD card to ensure that the files can be read on Mac OS
computers.
The base Concert radio system attempts to read these hidden files, but
cannot recognize them and may report that they are damaged. The
customer may need to scroll down in the file list or change folder levels
to display the playable audio files.

Figure 2. Hidden files. The file
names of hidden files start with a
period.

© 2014 Audi of America, Inc.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of
Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior
expressed written permission of the publisher.

Technical Service Bulletin
• The bit rate encoding of the audio files exceeds the maximum
allowed by the Concert radio system.
The Concert radio system can only play music files with a maximum bit
rate encoding of 320Kbps. If the maximum bit rate encoding of the files
exceeds 320Kbps, the file will not play.
The maximum bit rate encoding of an audio file can be checked with
the free software program MediaInfo (Figure 3), which can be
downloaded from http://www.sourceforge.net/.
Figure 3. File details displayed in
the MediaInfo software. The overall
bit rate (top box) is only 267Kbps,
but the maximum bit rate (bottom
box) is 404Kbps, which exceeds the
320Kbps limit.
For Scenario C:
Scenario C can result from the following cause:
• One vehicle has Audi Concert radio and the other vehicle has MMI 3G/3G+.
The maximum playable bit rate of the Concert radio system is 320Kbps. However, the maximum playable bit
rate of the MMI 3G/3G+ system is higher (refer to the owner’s manual for details). It is possible that audio files
that play on the MMI 3G/3G+ system will not play on the Concert radio system because of the different
maximum playable bit rates of the two systems.

Production Solution
Not applicable.

Service
For Scenario A and Scenario B:
1. Verify that the audio system is working correctly and is capable of playing one of the supported audio types
listed in the Technical Background by using a known good SD card with tested files.
If the known good files play in the customer’s vehicle, advise the customer to re-create their audio files in a
format that is supported by the Audi MMI system. If possible, demonstrate for the customer how to create
playable files. See the attached quick reference guide for instructions for encoding music files in iTunes. If
needed, share the guide with the customer.
2. If the customer is experiencing issues with hidden files on the SD card as a result of using iTunes on a Mac
OS computer, advise the customer to use the program “OptimUSB”. The program can be downloaded from
the official Mac App Store. When the program is used after the customer transfers music to the SD card, the
program will “clean” the SD card of any hidden files.
© 2014 Audi of America, Inc.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of
Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior
expressed written permission of the publisher.

Technical Service Bulletin
For Scenario C:
1. Explain the Technical Background of Scenario C to the customer.
2. If the customer would like to re-encode his or her music to a bit rate that is equal to lower than 320Kbs so that
it can be played on the Concert radio system, share the attached quick reference guide for instructions for
encoding music files in iTunes.

Warranty
This TSB is informational only and not applicable to any Audi warranty.

Additional Information
All parts and service references provided in this TSB (2020399) are subject to change and/or removal. Always
check with your Parts Department and service manuals for the latest information.

© 2014 Audi of America, Inc.

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All rights reserved. Information contained in this document is based on the latest information available at the time of printing and is subject to the copyright and other intellectual property rights of
Audi of America, Inc., its affiliated companies and its licensors. All rights are reserved to make changes at any time without notice. No part of this document may be reproduced, stored in a retrieval
system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, nor may these materials be modified or reposted to other sites, without the prior
expressed written permission of the publisher.