39 Four-wheel drive malfunction message, DTC C05ED00 is stored in the all-wheel drive control module
39 20 39 2051558/5 December 10, 2020. Supersedes Technical Service Bulletin Group 39 number 20-35 dated
August 21, 2020 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

Q5, SQ5

2018

All

Quattro Ultra

Q5, SQ5

2019

000001 - 124125

Quattro Ultra

A6, A7, S6,
and S7

2018 - 2019

All

Quattro Ultra

A6, A7, S6,
and S7

2020

000001 - 008938

Quattro Ultra

A4, A4
allroad, and
S4

2018

All

Quattro Ultra

A000001 - A021502

A4, A4
allroad, and
S4

2019

A5, A5
Cabriolet.
A5
Sportback,
S5, S5
Cabriolet,
and S5
Sportback

2018

Or

Quattro Ultra

N000001 - N001666

A5, A5
Cabriolet.
A5
Sportback,
S5, S5
Cabriolet,
and S5
Sportback

All

Quattro Ultra

A000001 –A073698
2019

Or

Quattro Ultra

N000001 - 010733

Condition
REVISION HISTORY
Revision

Date

Purpose

5

-

Revised Service (Updated which ODIS test plan results to follow)

4

08/22/2020

Revised Service (Updated instructions to reuse springs)

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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.

Revised Required Parts and Tools (Updated Vise part number)
3

06/17/2020

Revised Technical Background (Updated information and added photo)
Revised Service (Replacing shift fork inside differential)
Revised Warranty (Labor operations changed to include the new repair)
Revised Required Parts and Tools (Updated tools table)

Customer states:
 The message "four-wheel-drive malfunction" is sporadically shown in the instrument cluster.
Workshop findings:
The following DTC is logged in the all-wheel-drive control module, J492 (address word 0022):
 DTC C05ED00 (4WD/AWD Clutch "B" Stuck Engaged) with symptom code 29725.

Technical Background
Quattro Ultra shift fork inside the rear differential is
worn/faulty (Figure 1).

Figure 1. Worn/faulty shift fork.

Production Solution
Improved material in production.

Page 2 of 17
© 2020 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.

Service
Proceed as follows:
Complete the ODIS test plan for the DTC C05ED00 (4WD/AWD Clutch "B" Stuck Engaged) completely
according to Guided Fault Finding to rule out other reasons for the restricted function and to avoid an
unnecessary parts replacement:
 If the result of the test plan leads to replacing the rear differential or finds no defect, perform a short test
drive. If the same DTC returns after the test drive with the same symptom, the shift fork inside the rear
differential is at fault and must be replaced. Perform the repair as follows. Do not replace the complete
differential.


If the result of the test plan leads to replacing or repairing a different part (The All-Wheel Drive Clutch,
Driveshaft Speed Sensor G970, All Wheel Drive Clutch Actuator 2 V623, or any other part), follow the Guided
Fault Finding repair advice and this TSB does not apply.

1.

Drain the oil of the rear differential according to the repair manual.

2.

Remove the rear differential per the repair manual.

Tip: Although there are instructions available in the Elsa repair manual to perform this repair, the tools
utilized in Elsa have never been required tools. Our records indicate that few dealers have procured them as a
result. The repair shown in this TSB uses tools that are minimum required tools and one tool that will be auto
shipped to Audi dealers shortly. If you are missing a tool for this repair, please order it and continue with the
repair.
At the time of publishing this TSB, we have enough tools in stock to handle these repairs/orders. If the web site
shows no availability of a tool that you require, please call SBS directly at 1-800-892-9650 as they may have
stock that is not showing on the site.
3.

Place the differential on a workbench and remove the All-Wheel Drive Clutch Actuator 2 -V623- according
to the repair manual.

4.

Loosen the case bolts -1 to 9- and separate the
housing halves saving the bolts as they will be
reused for reassembly (Figure 2). Use care to
not damage the sealing surfaces.

Figure 2. Case bolts.

Page 3 of 17
© 2020 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.

5.

Mount the side carrier as shown below (Figure
3) to the VAS6095 using T40206, T40206/1A,
one long slotted arm from the VAS6095, 3350/2
(Figure 4 and Figure 5), three M10 flat washers
2mm thick each (Figure 5), one M10 x 1.5 x70
bolt (Figure 4 and Figure 5), and one M12 x 1.5
x 38 bolt (Figure 4).

Figure 3. Mounted side carrier.

Page 4 of 17
© 2020 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.

Figure 4. Mounting detail.
5a.

Figure 5. Mounting.

The passenger side differential mount attaches to the T40206/1A at hole #6 and the long slotted arm of the
VAS6095 attaches to threaded hole 5A using one of the M12 x 1.75 x 40 bolts from the VAS6095
engine/transmission stand (Figure 7). Alternately the long slotted arm of the VAS6095 can attach to
threaded hole 5B with any M12 bolt and a nut (bolt must be 50mm or longer).

Page 5 of 17
© 2020 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.

Figure 6. Mounting.
6.

Figure 7. Mounting.

Pull out the gear carrier (Figure 8, position 3)
using the VAS 251001 with VAS 251 001/2
(Figure 8, position 1) and thrust piece 30 – 555
(Figure 8, position 2).
Alternate puller tool T10040 with T10040/2. This
tool is harder to get jaws in the access holes but
it will work.
Alternate thrust pieces can also be used and a
test repair was performed not using a thrust
piece. If no thrust piece is used you may
damage the end of the puller or the shaft if too
much force is applied.

Figure 8. Puller arrangement.

Page 6 of 17
© 2020 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.

7.

Remove the gear carrier (Figure 9, position 1
and Figure 10). During this step, guide the shift
fork out of the clutch module (engagement
collar), then remove the shim (Figure 9, position
2).

Figure 9. Gear carrier and shim removal.

Figure 10. Gear carrier removal.

Page 7 of 17
© 2020 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.

8.

Remove the springs and save them for
reinstallation (Figure 11, position 1).
Remove the roller sleeves (Figure 11, position
2).

Figure 11. Shift fork assembly.
9.

Install an M8 flange nut (Figure 12, position 3)
onto the T10172/9 (Figure 12, position 4).
Tension the gear carrier in the vise as shown
(Figure 12, position 1) using the plastic or brass
soft jaws (Figure 12, 2). You may need a 2nd
technician to assist you in holding the carrier.
Position the sleeve provided in the repair kit Part
# 0B0 598 082 (Figure 12, position 6) between
the shift fork (Figure 12, position 8).
Press out the bearing pin (Figure 12, position 5)
until the thrust piece stops (Figure 12, position
4).

Figure 12. Pin removal.

The bearing pin (Figure 12, position 5) remains
in the shift fork (Figure 12, position 8) together
with the sleeve (Figure 12, position 6).
Repeat the procedure on the other side.

Page 8 of 17
© 2020 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.

10.

Insert the pins (Figure 13, position 1) into the
holes of the gear carrier.
The pins have to be easy to move in and out of
the holes

Figure 13. Pin checking.
11.

Insert the new shift fork from the repair kit
(Figure 14, position 2) into the gear carrier, and
in doing so pay attention to the right installation
position.
Flap the latch (Figure 14, position 1) outward for
installation.
Insert the shift fork (Figure 14, position 2) into
the recess of the gear carrier -arrow-.
Partially insert the new pins provided in the
repair kit (Figure 14, position 3), to secure the
shift fork for the next step (Figure 14, position
2).
Figure 14. Installing a new shift fork.

Page 9 of 17
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