Technical Service Bulletin
87 Unpleasant odor is coming from the heating and ventilation system
87 23 44 2010146/18 June 14, 2023. Supersedes Technical Service Bulletin Group 87 number 22-25 dated April
16, 2022 for reasons listed below.
Model(s)

A5, and S5
A4 Avant

Year

VIN Range

Vehicle-Specific Equipment

All

Not Applicable

2008 – 2015
2018 – 2020
2009 - 2012
2009 – 2015

A4

2017 – 2020
2009 – 2015

Q5

2018 - 2020

S4, A5 Cabriolet, 2010 – 2015
S5 Cabriolet
2018 – 2020
A4 allroad

2013 – 2015
2017 – 2020

RS 5 Cabriolet,
and Q5 Hybrid

2013 - 2015

RS 5

2013 – 2015
2018 – 2019
2013 – 2015

SQ5

2018 – 2020

Condition
REVISION HISTORY
Revision

Date

Purpose

18

-

Revised header (MY 2008 – 2015 and MY 2017 - 2020 applicable models only)
Revised Service (Remove procedural references to models not addressed)
Revised Warranty (Remove warranty table)
Revised Required Parts and Tools (Remove treatment solution requirement for 2evaporator cleaning)

17

04/17/2022

Revised header (Added model year 2023 and new model codes)

Page 1 of 4
© 2023 Audi of America, Inc.
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
16

05/04/2021

Revised header (Added model year 2022 and new model codes)
Revised Warranty (Remove test rides)

Customer states:
• There is an unpleasant, musty odor coming from the heating and ventilation system.
• The odor usually occurs when the vehicle has been sitting unused for five hours or more.
• The odor usually occurs within 20 to 60 seconds after the vehicle is started.

Technical Background
Condensation, which is a normal condition in all A/C systems, can cause a musty odor.
If the odor is noticeable in the vehicle when the engine is not turned on, the cause may be mold and mildew in the
passenger compartment, and not be related to the A/C system. All other possible sources of the odor must be
investigated before this bulletin can be performed. Before proceeding, consider the following:
• The evaporator housing drain must be open and free of debris.
• The cabin must be sealed with no water ingress into the passenger compartment.
• The plenum drains must be clear and free of debris.
• The pollen filter must be clean and free of moisture.

Production Solution
Not Applicable

Service
Contaminants are effectively neutralized by the Aircomatic® II Ultrasonic Climate System Cleaner (VAS 6189A)
and Airco-Clean® Ultrasonic Air Conditioning Treatment (VAS 6189/1). No other cleaning methods are permitted.
1.

If the vehicle is equipped with an in-cabin pollen filter, remove the pollen filter element and reinstall its cover
before proceeding.

2.

Start the engine.

3.

Adjust the following climate control settings (Figure 1):
• Set the temperature to its lowest setting.
• Set the fan speed to its lowest setting.
• Set the airflow direction to the dash vents only.
• Activate recirculation and ECON modes.

•
Figure 1. Climate control settings.

Page 2 of 4
© 2023 Audi of America, Inc.
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
4.

Thoroughly shake a 100ml bottle of treatment and empty it into
the filling chamber (Figure 2).

Figure 2. Pouring the treatment into the
filling chamber.
5.

Connect the outlet tube (Figure 3).

Figure 3. The connected outlet tube.
6.

Place the cleaning unit into the passenger side footwell, ensuring that the unit is as level as possible.

7.

Connect the unit power cord, and route it through one of the
windows, which should be slightly open (Figure 4). All other
windows and the sunroof should be completely closed.

Figure 4. The window is slightly open so
that the cord can pass through.
8.

Turn the unit on and position the outlet tube so that the vapor is drawn into the recirculation air intake
(generally in the passenger side footwell area; see appropriate repair information for exact location).

9.

Close all doors. The atomized cleaning fluid will begin to come out of the vents. After 15-20 minutes, the
treatment is complete and the machine stops automatically.

10. After the procedure, air the vehicle out for approximately ten minutes.
11. Check the Aircomatic® manual for instructions for unit maintenance after each use.

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

Required Parts and Tools
Always check with your Parts Department and/or ETKA for the latest information and parts bulletins.

Page 3 of 4
© 2023 Audi of America, Inc.
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
Part Number

Part Description

Quantity

See ETKA

Fasteners, Bolts, Nuts, and Screws as needed See ETKA/ELSA
per the Repair Manual

VAS 6189/1

Airco-Clean® Ultrasonic Air Conditioning
Treatment (100ml bottle)

Tool Number

Tool Description

1 bottle

VAS 6189B

Aircomatic® II Ultrasonic Climate System Cleaning unit

Additional Information
All parts and service references provided in this TSB (2010146) are subject to change and/or removal.
©2023 Audi of America, Inc. All rights reserved. The 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.

Page 4 of 4

© 2023 Audi of America, Inc.
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.