A6921682056421_4

69 Seat belt warning or Pre Sense warning appears sporadically while driving, DTC B101C07 stored in the
airbag module
69 21 68 2056421/4 August 5, 2021. Supersedes Technical Service Bulletin Group 69 number 20-57 dated
August 31, 2020 for reasons listed below.
Model(s)
Year
VIN Range
Vehicle-Specific Equipment
A6, A7, A8,
S8, and Q8
2019 - 2022
All
Not Applicable
A6 allroad,
S6, RS 6,
S7, RS 7,
A8 PHEV,
Q7, SQ7,
SQ8, RS
Q8, Audi etron quattro,
and Audi etron
Sportback
2020 - 2022
All
Not Applicable
A6 Avant,
RS 6 Avant,
and A7
PHEV
2021 - 2022
All
Not Applicable
Condition
REVISION HISTORY
Revision
Date
Purpose
4
-
Revised header (Added Model Year)
3
09/01/2020
Revised header (Added MY20-21 Q7 & MY21 models)
2
02/06/2020
Revised title
Customer states:
 While driving, the seat belt and/or the Pre Sense warning appears sporadically in the driver information system
(DIS).
Workshop findings:
The following DTC is stored in the airbag control module/safety computer, J234 (address word 0015):
 DTC B101C07 (Driver seat belt switch mechanical malfunction).
Page 1 of 3
© 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
The Safety Computer continuously monitors the status of the seat belt latch switch, E24. If a seat belt extender, a
seat belt cheat device is installed or the seat belt is continuously buckled, the Safety Computer receives the
constant signal that the seat belt is latched. If the Safety Computer does not see a change in the belt latch switch
signal within five drive cycles, it stores DTC B101C07, and the Pre Sense Warning appears in the DIS in the
assumption that a seat belt cheat device is installed.
A drive cycle consists of:
1. Unlock door.
2. Open door.
3. Close door.
4. Latch seat belt.
5. Turn on ignition and drive.
6. Park.
7. Unlatch seat belt.
8. Turn off ignition.
9. Open door.
10. Close door.
11. Lock door.
Production Solution
Not applicable.
Service
1. Connect vehicle to ODIS Service and perform GFF.
2. If the DTC B101C07 is stored in the airbag control module/safety computer follow all applicable GFF test
plans.
3. If the GFF indicates that the seat belt latch switch is not defective, inform the customer that the use of a seat
belt extender, seat belt cheat device or leaving the seat belt continuously buckled could cause this concern.
4. One drive cycle with latching and unlatching the seat belt is sufficient to switch the DTC B101C07 from static
to sporadic and to turn off the Pre Sense warning in the instrument cluster.
Page 2 of 3
© 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.
Warning:
The risk of serious or fatal injury increases if the seat belt is not fastened, if it is worn incorrectly, or if it is
damaged.
See owner’s manual for additional information and warnings.
Note:
Parts replacement does not solve this issue. Claims for replaced parts will be subject to review.
Warranty
This TSB is informational only and not applicable to any Audi Warranty.
Additional Information
All parts and service references provided in this TSB (2056421) 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 3 of 3
© 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.