91 Audi phone box customer registration form and reporting obligation by the customer to MNO
91 21 20 2051720/4 August 10, 2021. Supersedes Technical Service Bulletin Group 91 number 19-76 dated
August 7, 2019 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

All

2019 - 2022

All

Audi phone box

Condition
REVISION HISTORY
Revision

Date

Purpose

4

-

Revised header (Added vehicles)
Revised Service (Defined PR Code GB0/GB2)

3

08/07/2019

Revised Service (Indicated MY20 will not have sticker installed and added
information for what to do with missing serial number)

2

01/15/2019

Revised Technical Background (Corrected PR Code GB2)
Revised Service (Added FCC ID)

The customer has inquired about the Audi phone box
(Figure 1) and/or wants to know more about the registration
form to be submitted to the customer’s Mobile Network
Operator (e.g. AT&T, T-Mobile, Verizon, Sprint, etc.).

Figure 1. Audi phone box with wireless charging.

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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
Audi phone box background information:
Starting with the MY19, vehicles sold in the USA can be equipped with the Audi phone box system (PR Code
GB2). The Audi phone box system includes a Qi-compatible wireless charging pad and a wireless connection to
an external LTE antenna located outside the vehicle (Figure 1). Although by design, the system is a “signal
compensator” only moving the signal to outside the vehicle, the FCC has classified this type of device as a “signal
booster”. It is important to note to the customer that this system does not appreciably amplify the signal from the
mobile phone to the network, as with older style signal boosters which were in use before 2013. Thus, if the
customer is unable to receive a signal from the Mobile Network Operator (MNO) to their mobile device while
standing outside the vehicle, using the Audi phone box inside the vehicle will NOT improve the signal strength.
From the FCC.gov website:
The FCC issued a Report and Order on February 20, 2013, that includes rules and policies that will enhance
wireless coverage for consumers, particularly in rural, under-served, and difficult-to-serve areas by broadening
the availability of signal boosters while ensuring that boosters do not adversely affect wireless networks. New
FCC rules for wireless signal boosters came into effect on March 1, 2014. Consumers can read the Consumer
Advisory for consumers who own signal boosters here: https://www.fcc.gov/document/consumer-advisoryinformation-consumers-who-own-signal-boosters.
Audi Dealers MUST provide the registration form to the customer at the time of delivery.
Audi dealers must provide to the vehicle owner the customer
registration form (Figure 2) found in the glovebox. This form is
installed at the port of arrival in the USA. The form contains
the Make, Model, and a Serial number of the Audi phone box
installed in the vehicle. Customers must submit this
information to their personal cell phone service provider
(MNO).

Figure 2. Customer registration form.

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.

Below is a list of the known registration sites for the four most common providers operating in the USA. Please
keep in mind these URLs are subject to change at any time. If the URL does not work, then please ask the
customer to contact their provider’s support center to find the latest registration process which will be specific to
their provider:
 AT&T: https://securec45.securewebsession.com/attsignalbooster.com/.
 Sprint: https://www.sprint.com/en/legal/signal-boosters.html.
 T-Mobile: https://www.signalboosterregistration.com/.
 Verizon: https://www.verizonwireless.com/solutions-and-services/accessories/register-signal-booster/.

Production Solution
Not applicable.

Service
If the customer cannot locate the form to register the factory-installed Audi phone box, please download and print
off the form which is attached to this TSB. Additionally, the form can be downloaded from ServiceNet located at
Audi >> Technician References >> Electrical >> Audi phone box registration form.
How to fill out the form:
The three main fields on the form are Make, Model, and Serial number.
Make:
 For all Audi vehicles, the Make will be “FKW”.
Model:
 For all Audi vehicles, the Model will be the Audi phone box part number, 4M0.035.456A. For MY19, the part
number is the same for all Audi vehicles with the Audi phone box.
Serial Number:
PR code GB0:
Phone box is not equipped. There will be no serial number registered in ELSA as the phone box is not present in
the vehicle. The vehicle can still have a wireless charging pad.

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.

PR code GB2:
The serial number is the only value which will change
for each vehicle. Each Audi phone box system installed
will have a unique serial number. This serial can be
found in Elsa under the vehicle information section
(Figure 3). Additionally, for some MY19 models only
(except D5, C8, and R8), a sticker will be placed in the
rear luggage water drain channel (Figure 5) with the
installed Audi phone box Serial number. MY20 vehicles
and newer, may not have the sticker installed and thus
the only location for the serial number is in Elsa.
Figure 3. Serial number in Elsa.

What to do if the serial number cannot be accessed in Elsa (independent used car sales) or if the sticker
was removed by the owner or a third party (second owner scenario):
If the serial number cannot be accessed via Elsa, please reference the official repair manual to locate the Audi
phone box module. For most vehicles, the phone box is located in the passenger side rear luggage
compartment behind the trim panel.
The serial number sticker will be placed on the outside
of the phone box control module near the part number
label. If no sticker is attached to the module, then the
serial number will be documented on the part number
label (Figure 4). Take a photo of the part label and then
reference this photo to properly document the serial
number onto the customer registration form.

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.

Figure 4. Phone box module part label.
FCC ID: RK7MBC-NAR
Some providers may require the user to supply the FCC ID for the Audi phone box upon registration. This data is
not an FCC requirement to Audi nor to the customer. Because of this, the FCC ID field is not listed on the
customer registration form. If the MNO requires the FCC ID for registration, then please provide the customer
with the ID listed above. The FCC ID is the same for all vehicles.

Figure 5. Sticker locations on various Audi models only for MY19.

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.

For MY19 A8 (D5), A6/A7 (C8), and R8; the serial
number is located on the factory production sticker
(Figure 5).
This sticker should already be placed in the owner’s
manual (Figure 6). If the sticker is not in the owner’s
manual, it can be found in the spare wheel well area or
front luggage area of the R8. Please relocate the
sticker to the owner’s manual.

Figure 6. Factory production sticker.

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

Additional Information
All part and service references provided in this TSB (2051720) 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.
©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.