21 Engine difficult to start, turbocharger is damaged V8 4.0TFSI
21 21 37 2044640/10 August 31, 2021. Supersedes Technical Service Bulletin Group 21 number 20-36 dated
October 29, 2020 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

RS7

2014 - 2016

All

4.0L

S8+, RS7+

2016

All

4.0L

A8

2017

000001 - 019190

4.0L

S8, S8+

2017

000001 - 901368

4.0L

S6, S7

2017

000001 - 115286

4.0L

RS7, RS7+

2017

000001 - 904264

4.0L

A8, S6, S7,
and S8

2013 - 2016

All

4.0L

Condition
REVISION HISTORY
Revision

Date

Purpose

10

-

Revised Service (Updated Step 1 and 9)
Revised Warranty (Updated Claim Type and Labor Operations)
Revised Required Parts and Tools (Added and updated tool part numbers)

9

10/30/2020

Revised Required Parts and Tools (Updated part number)

8

08/26/2019

Revised Additional Information (Updated resources)

Customer statement:
 The engine cannot be started or only with difficulty.
 The engine makes unusual noises when accelerating.
 The engine has reduced performance.
Workshop findings:
Damage on turbocharger impeller fins causes increased free play on the impeller shaft of the turbocharger or
there is a broken impeller shaft.

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© 2021 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 Background
Damage to the turbocharger is rarely directly the result of turbocharger failure. Therefore, it is important to
perform further checks to find the root cause, to avoid repeat repairs.
Known causes for turbocharger damage:
 Performance increases by tuned ECM.
 Non-compliance with service intervals.
 Incorrectly fitted oil filter element.
 Leaks in the intake tract allowing outside unfiltered air and debris into the turbocharger.
 Poor oil supply to the turbocharger.
Note:
If the vehicle has any DTCs related to the turbocharger boost/regulation the complete GFF Test plan must be
completed and repairs performed before determining if further repairs are necessary.

Production Solution
Optimized oil strainer 079115175G for oil supply lines to turbochargers in the cover in the inner valley of
the engine. The oil strainer and check valve 079103175C must always be replaced to ensure proper oil
flow to the turbochargers.

Service
Watch the June Hot Topics before proceeding with the below repair
at: https://audiacademy.kzoplatform.com/player/medium/1186073779801953796
(Figure 1).

Figure 1. QR Code for supporting video.

Page 2 of 8
© 2021 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.

1 Perform the Guided Functions with the diagnosis tester: "01 check warranty information." Then check for an
. entry with the vehicle data in Elsa under the warranty key.
 All information must be documented with pictures with the attached Checklists completely filled out and
stored with the Repair Order.
2 Check the hardware version of the engine
. control module. An X version indicates that the
engine control module was replaced/or is
modified (Figure 2).

Figure 2. Correct hardware version number.
Perform a visual check of the engine control module (check
for irregularities of the housing of the control module) and
check whether a tuning box is fitted (also in the area behind
the diagnostic interface).
3 Check the intake tract for leaks. Review the repair history for possible previous repairs on the intake tract.
.
4 Measure the oil pressure at idle and 2000 rpm according to Elsa.
.
5 Visually assess the condition of the damaged turbocharger from both sides. No oil marks (charge air and
. exhaust side) could be another indication of poor oil supply to the turbocharger.
6 Check the oil filter for correct installation and correct filter part number 079115561J. If the oil filter is not
. centrally fitted, the engine oil may not be filtered, entering the oil supply of the turbocharger due to the
crooked position of the oil filter element.
7 Check the installation of the oil filter bypass valve according to service measure 17F2.
.
Note:
This TSB is not replacing any Elsa Repair Manual instructions, this TSB is meant to supplement the Repair
Manual. See Elsa, Engine >> 8-Cylinder Direct Injection 4.0L 4V TFSI Engine >> 21 Turbocharger >>
Turbocharger, Removing and Installing.
8 Replace the turbochargers as well as the oil strainer (do not clean the strainer) and check valve in the
. inner valley of the engine according to Elsa and observe all instructions, including:

Page 3 of 8
© 2021 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.

 Check the oil supply line for through flow and oil deposits.
 Check the oil drain hoses for through flow and oil deposits.
 Filling the turbocharger at the supply line connections with engine oil.
 Replacement of the turbocharger wastegate vacuum actuator is no longer necessary. The vacuum
actuator and actuator rod can be reused. The existing clip must not be reused and must always be
replaced. The retaining clip is now available in ETKA.
9 Change the engine oil including the oil filter. Check the drained oil and oil filter for particles. If particles are
. found, flush the engine and new turbocharger with the new engine oil at an increased engine speed for 15
minutes.
 If no particles were found in the drained engine oil or oil filter, another oil change is not necessary and the
engine does not have to be flushed at an increased idle speed.
 To ensure the turbocharger is supplied with enough oil, let the engine run at idle for approximately one
minute after starting, do not increase rpm.
 Send the oil strainer in a small zip lock bag (do not clean the strainer), back to AoA with the
supplied return address label as soon as the oil strainer is removed. Include a copy of the Repair
Order and both the completed check sheets.
Note:
Failure to follow the TSB and Elsa instructions may lead to premature turbocharger failure which may be
reviewed by Warranty.
Warranty may review the claim and request the turbocharger that was replaced. Documents and pictures
may be requested to be sent to the Warranty Parts Return Center.

Warranty
Claim Type:

 110.
 If the vehicle is outside any warranty, this Technical Service Bulletin is informational
only.

Service Number:

S642

Damage Code:

0010

Labor Operations:

Turbocharger replace

2130 5671

See SRT with
associated
operations

Completing both check sheets

2130 9999

50 TU

Page 4 of 8
© 2021 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.

Diagnostic Time:

Oil pressure check

1703 0199

80 TU

Check intake and exhaust system for
debris, additional time is included in
Turbocharger remove + reinstall

2130 0199

20 TU

Remove + reinstall oil strain and check
valve

1726 2099

70 TU

Check that the oil bypass valve is fitted
correctly

1701 0199

10 TU

Engine oil and filter change - once

1701 1799

40 TU

Engine oil and filter change – twice. Flush
oil circuit

1701 1799

100 TU

Both turbochargers remove + reinstall

2130 2071

See SRT with
associated
operations

Air intake distributor remove + reinstall
without night camera and radar sensor

2446 1921

See SRT with
associated
operations

Air intake distributor remove + reinstall
without night camera and radar sensor

2446 1923 (RS7
only)

See SRT with
associated
operations

Night vision Camera System adjustment (if
equipped)

9080 1550

See SRT with
associated
operations