91 SOS warning displayed in instrument cluster, DTC B191604 is stored in the gateway control module
91 21 32 2051664/4 September 16, 2021. Supersedes Technical Service Bulletin Group 91 number 20-58 dated
December 18, 2020 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

A4, A4
allroad, S4,
A5, A5
Cabriolet,
A5
sportback,
S5, S5
Cabriolet,
S5
sportback,
Q5, SQ5,
Q7, and
SQ7

2018

All

connected gateway

Condition
REVISION HISTORY
Revision Date

Purpose

4

Revised Service (Updated Step 9 and 10)

-

Revised Warranty (Updated Labor Operation)
3

12/19/2020

Revised Warranty (Updated Labor Operations)

2

02/05/2019

Revised title
Revised header (Remove MY2019)
Revised Production Solution (Updated information)
Revised Warranty (Updated Labor Operations)

Page 1 of 6
© 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.

Customer states:
 The warning message “Emergency call function:
malfunction! Restricted functionality. Please contact
Service” appears in the instrument cluster (Figure 1).

Figure 1. The warning message is shown in the
instrument cluster.
Workshop findings:
The following DTC may be stored in the gateway control module, J533 (address word 0019) as static or
intermittent:
 DTC B191604 (Backup battery Faulty).

Technical Background
Incorrect software parameter for the connected Gateway’s back-up battery charge monitoring. The system must
be reset by performing a manual discharge of the connected Gateway’s backup battery.

Production Solution
The part is no longer used in production.

Service
1. Perform a manual discharge of the connected gateway’s backup battery by removing constant power
(KL30) and accessory power (KL15), while KL15 is switched on.
This will force the connected gateway to draw power from the backup battery, lowering the voltage of
the backup battery. Several discharge cycles may be needed for the voltage of the backup battery to
fall within the specified parameters.

Page 2 of 6
© 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.

Note:
The steps for the manual discharge, 4 through 8, are to be performed with the engine OFF, and without a
12V charger on the vehicle.
2.

Gain access to fuse panel SB, located behind the driver’s side footwell cover. Consult the Elsa
Repair Manual for instructions on accessing fuse panel SB.

3.

Locate the two fuses which supply constant power (KL30) and accessory power (KL15) to the
connected gateway. Consult the wiring diagram or Owner’s Manual for the fuse location and size.

4.

Ensure that accessory power (KL15) is ON.

5.

Remove the two fuses identified in Step 3.

6.

Wait 30 seconds with both fuses removed.

7.

Reinstall the two fuses.

8.

Turn off accessory power (KL15).

9.

Repeat steps 4 through 8 six additional times. This will result in a total of seven discharge cycles.

10. Following seven discharge cycles, clear the fault memory for the connected gateway module:
 In ODIS GFF, recheck the fault memory of the connected gateway.
 The DTC should now be passive/sporadic and should not return after clearing the fault memory.
If the fault does not clear and is marked as active/static, then replace the connected gateway’s
backup battery. Consult the Elsa Repair Manual for instructions on replacing the connected
gateway’s backup battery. Consult the parts catalog for the correct part number of the connected
gateway’s backup battery.

Connected Gateway Fuse Location Table Reference:
KL30

KL15

Model

Fuse Number Panel

Location

Fuse Number Panel

Location

Q7

SB7

ST5

Figure 2.2

SB2

ST4

Figure 2.1

Q5

SB7

ST2

Figure 3.1

SB2

ST4

Figure 3.2

A4

SB7

ST2

Figure 3.1

SB2

ST4

Figure 3.2

A5

SB7

ST2

Figure 3.1

SB2

ST4

Figure 3.2

Page 3 of 6
© 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.

Figure 2. Q7 Driver’s Side Footwell Fuse Box. 1: KL15 Fuse. 2: KL30 Fuse.

Figure 3. A4, A5, and Q5 Driver’s Side Footwell Fuse Box. 1: KL30 Fuse. 2: KL15 Fuse.

Warranty
Claim Type:

 110 up to 48 Months/50,000 Miles.
 G10 for CPO Covered Vehicles – Verify Owner.
 If the vehicle is outside any warranty, this Technical Service Bulletin is informational
only.

Service Number:

9035

Damage Code:

0039

Page 4 of 6
© 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.

Labor Operations:

All models:
Check back-up battery for telematics

9178 0199

15 TU

7035 1900

See SRT with
associated
operations

7035 1999

20 TU

A4, A5:
Remove and install footrest

Q5, Q7:
Remove and install foot rest

As required and only if the battery is replaced:
A4, A5, and Q5:
Telematics emergency battery replace

9178 5550

See SRT with
associated
operations

Telematics emergency battery replace

9178 5550

See SRT with
associated
operations

Data bus control module remove + reinstall

9035 1999

30 TU

Front seat remove + reinstall

7201 1900

See SRT with
associated
operations

GFF – Checking and clearing fault codes
included in existing labor operations

0150 0000

Time stated on
the diagnostic
protocol (Max
100 TU)

Road test prior to service procedure

No allowance

0 TU

Road test after service procedure

No allowance

0 TU

Q7:

Diagnostic Time:

Claim Comment:

As per TSB #2051664/4

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.

Page 5 of 6
© 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.

Required Parts and Tools
Always check with your Parts Department and/or ETKA for the latest information and parts bulletins.
Parts are only needed if the fault does not clear.
Part Number

Part Description

Quantity

4M0907486

Battery for emergency. operation

01 (As needed)

See ETKA

Fasteners, Bolts, Nuts, and Screws as needed per the
Elsa Repair Manual

See ETKA/ELSA

Additional Information
All parts and service references provided in this TSB (2051664) are subject to change and/or removal.
©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.

Page 6 of 6
© 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.