Technical Service Bulletin
19 Engine: cooling system - engine overheats, red coolant temperature warning, MIL on - 4.0 ltr. V8 TFSI;
P029900
19 24 74 2074303/6 December 4, 2024. Supersedes Technical Service Bulletin Group 19 number 24-70 dated
November 6, 2024 for reasons listed below.
Model(s)

Year

RS 6 Avant, and
RS 7

2021 – 2024

A8

2019 – 2021

S8

2020 – 2024

SQ7, and SQ8

2020 – 2025

RS Q8

2020 - 2023

VIN Range

Vehicle-Specific Equipment

All

4.0l V8 TFSI

Condition
REVISION HISTORY
Revision

Date

Purpose

6

-

Revised Warranty (Revised accounting instructions)

5

11/06/2024

Revised Warranty (Revised accounting instructions)

4

09/23/2024

Revised Service (Measure description changed)

Customer statement:
•

The engine is overheating.

•

The coolant temperature gauge is in the red.

•

The red coolant temperature warning light appears in the instrument cluster.

and/or
•

Exhaust emissions warning lamp is on.

Workshop findings:
•

The customer complaint can be reproduced, and the engine temperature is in the red. In addition, the event
memory entry P0299 (Turbo/Super Charger Underboost) may be logged in some cases.

or
•

Event memory entry P0299 (Turbo/Super Charger Underboost) logged.

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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 1
EA825 V8 TFSI engines across all power classes are currently equipped with a switchable mechanical coolant
pump.
It is activated via the electric changeover valve N649.
When N649 is activated, it switches a vacuum to the mechanical coolant pump. This pushes a locking sleeve over
the pump impeller, which can cause coolant to stagnate.
When N649 is not activated, no vacuum is switched to the mechanical coolant pump, and the coolant pump is not
covered. In this case, the coolant is pumped through the coolant pump impeller.
The charge pressure control for the EA825 V8 TFSI turbochargers is electropneumatic.
This means that charge pressure positioners V465 and V546 are electropneumatic pressure converters.
Depending on activation (PWM) by the engine control unit, they are able to induce a calculated negative pressure
(characteristic curve). This determines the opening path of the wastegate. They are open when they are not
activated.
SSP 676 contains more information on the EA825 V8 TFSI engine cooling system.

Production Solution
Not applicable.

Service
If the coolant temperature in the vehicle is too high:
Remove the vacuum hose on the mechanical coolant pump (number 13 in Figure 1).
Check whether this results in lower engine coolant temperatures.
If the coolant temperature drops, replace the electric changeover valve for the switchable mechanical coolant
pump N649 according to the Workshop Manual.
Also check whether there are traces of coolant in the vacuum hose between the mechanical coolant pump and
N649, or in the vacuum connection of N649. If there are traces of coolant, please also replace the switchable
mechanical coolant pump and the vacuum hose between the mechanical coolant pump and N649 according to
the Workshop Manual and provide images.
If the coolant temperature in the vehicle is not too high, but the exhaust emissions warning lamp is on
and event memory entry P0299 (Turbo/Super Charger Underboost) is logged:
Check the vacuum system for leaks. If a leak is detected on N649, replace N649 according to the Workshop
Manual.
Also check whether there are traces of coolant in the vacuum hose between the mechanical coolant pump N649,
or in the vacuum connection of N649. If there are traces of coolant, please also replace the switchable
mechanical coolant pump and the vacuum hose between the mechanical coolant pump and N649 according to
the Workshop Manual and provide images.

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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

When billing, a video that clearly documents the complaint should be uploaded to DOC-IT.
• To ensure a reference to the vehicle, the video must include the VIN number and the date.
• Please ensure that the video documentation does not show any persons and/or faces, license plates,
or customer data.

Figure 1. Assembly overview – coolant pump/thermostat incl. switchable mechanical coolant pump, number 12.

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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

Figure 2. Assembly overview – vacuum system incl. N649, number 9.

Warranty
Claim Type:

•

Service Number:

Case 1: Both N649 and the coolant pump have been replaced due to traces of
coolant in the vacuum line or in N649. Use service number: 1950

© 2024 Audi of America, Inc.
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If the vehicle is outside of any warranty, this Technical Service Bulletin is
informational only.

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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
Case 2: Only N649 replaced due to no traces of coolant in the vacuum line or in
N649. Use service number 1985.
Damage Code:

Case 1: 050
Case 2: 010

Labor Operations:

Claim Comment:

Remove and install valve N649

1984 19xx

See SRT with
associated operations

Remove and install coolant pump (if
necessary)

1950 19xx

See SRT with
associated operations

GFF

0150 0060

Labor according to the
diagnostic log

As per TSB 2074303/6

All warranty claims submitted for payment must be in accordance with the Audi Warranty Policies and Procedures
Manual. Claims are subject to review or audit by Audi Warranty.

Additional Information
All part and service references provided in this TSB (2074303) are subject to change and/or removal. Always
check with your Parts Department and/or ETKA for the latest information and parts bulletins. Please check the
Repair Manual for fasteners, bolts, nuts, and screws that require replacement during the repair.
©2024 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.

© 2024 Audi of America, Inc.
Internal

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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.