Technical Service Bulletin
27 48V Vehicle electrical system warning, DTC P0CA700 and/or U046900 stored in the starter/generator
control module/ECM
27 22 41 2058831/4 March 2, 2022. Supersedes Technical Service Bulletin Group 27 number 21-40 dated
December 6, 2021 for reasons listed below.
Model(s)
Year
S6, S7, RS
7, S8, R8,
and R8
Spyder
2018
A6, A7, A8,
and S8
2018 – 2021
Q8
2019 – 2021
A8 e quattro
2020
A6 allroad,
S6, S7, S8,
SQ7, SQ8,
RS Q8, R8,
and R8
Spyder
2020 – 2021
RS 6 avant,
A7 e
quattro, and
A8 e quattro
2021
VIN Range
Vehicle-Specific Equipment
All
48 V Battery
Condition
REVISION HISTORY
Revision
Date
Purpose
4
--
Revised Warranty (Updated Labor Operation)
3
12/06/2021
Revised Condition (Added customer statements)
Revised Technical Background (Added information)
Revised Service (Added photo and new Steps 1-2)
Revised Warranty (Added Labor Operation)
2
04/01/2021
© 2022 Audi of America, Inc.
Revised header (Added MY21)
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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
Revised Service (Updated SVM Table)
Customer states:
• Intermittently a warning for the 48V vehicle electrical system is displayed in the instrument cluster.
Additionally, the customer may state:
• “The vehicle does not start.”
• “The vehicle stalled.”
• “The battery is dead.”
Workshop findings:
One or more of the following DTC(s) may be stored relating to the battery management 2 (Battery 48V) control
module, J1120 (address word 0021) and/or in the engine control module (ECM), J623 (address word 0001):
Battery management 2 (Battery 48V) control module, J1120 (address word 0021):
• DTC P0CA700 (hybrid battery discharge current too high static or sporadic).
ECM, J623 (address word 0001):
• DTC U046900 (invalid data received from starter/generator control module).
Technical Background
The software needs to be updated in the starter/generator control module, C29 (address word 00CC).
If the warning shown in the instrument cluster for the 48V vehicle electrical system is ignored, the 12V system may
drain, resulting in a vehicle stall or no start condition.
Production Solution
Updated software version implemented in production.
Service
© 2022 Audi of America, Inc.
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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
1. If DTC U046900 is found in the ECM, J623 (address word 0001), check the expanded ambient conditions of this
DTC for the value of “Starter generator, actual mode 48V.”
2. If the expanded ambient conditions value for “Starter generator, actual mode 48V” is 5 (Figure 1) for DTC
U046900, then replace the starter generator. If no value is displayed, please submit an ODIS feedback.
Figure 1. DTC U046900 with Expanded ambient condition “Starter generator, actual mode 48V” value of 5 in
the engine control module (ECM), J623 (address word 0001).
SVM Update Instructions
3. Follow all instructions in TSB 2011732: 00 Software Version Management (SVM), operating instructions.
4. Update the starter/generator control module, C29 (address word 00CC) using the SVM action code as listed in
the table below, if necessary:
Model
Old Hardware
Old Hardware
Old Software
Old Software New
SVM Code
Part Number
Version
Part Number
Version
Input
Version
(or lower)
© 2022 Audi of America, Inc.
Software
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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
(or higher)
A6, A7, Q7,
4N0903028
and Q8
(H, J, M, and N)
4N0903028
H17
(F, G, H, J, M,
523
527
CCA001
and N)
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:
2726
Damage Code:
0040
Labor Operations:
Software Update (Includes checking for DTCs)
0151 0000
Only if update required
Time stated on
the diagnostic
protocol (Max
100 TU)
Expanded ambient condition “Starter generator, actual mode 48V” value of 5 only:
Replace starter-alternator
2726 XXXX
See SRT with
associated
operations
Diagnostic Time:
GFF – Only if part replaced
0150 0000
Time stated on
the diagnostic
protocol (Max
100 TU)
Road test prior to the service procedure
© 2022 Audi of America, Inc.
No allowance
0 TU
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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
Road test after the service procedure
Claim Comment:
No allowance
0 TU
As per TSB 2058831/4
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.
Additional Information
The following Technical Service Bulletin(s) will be necessary to complete this procedure:
• TSB 2011732: 00 Software Version Management (SVM), operating instructions.
All part and service references provided in this TSB (2058831) 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.
©2022 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.
© 2022 Audi of America, Inc.
Page 5 of 5
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.