Technical Service Bulletin
01 Idle speed characteristic during cold start
01 12 57 2028344/3 October 29, 2012. Supersedes Technical Service Bulletin Group 01 number 12-51 dated
July 18, 2012 for reasons listed below.
Model(s)

Year

VIN Range

Vehicle-Specific Equipment

Cabrio

2007-09

Engine BKH

A4

2005-09

Engine BKH

A6

2005-09

Engine BKH

S5

2008-12

Engine CAUA

S6

2007-11

Engine BXA

S8

2007-09

Engine BSM

R8 V8

2008-10

Engine BYH

R8 V8

2011-13

R8 V10

2009-13

Engine BUJ

R8 V10

2012-13

Engine CMPA

RS 5

2013-2014

Engine CFSA

S6

2013-2015

Engine CEUC

S7

2013-2015

Engine CEUC

S8

2013-2015

Engine CGTA

A8 4.0T

2013-2015

Engine CEUA

Engine CNDA

All

Condition
REVISION HISTORY
Revision

Date

Purpose

3

-

Revised header data ( New models added )

2

7/18/12

Revised header data

1

1/13/2012

Original publication

Noises/inconsistent engine operation after cold start during the catalyst heating phase.
The customer may interpret this engine roughness as misfiring.

Page 1 of 3
© 2012 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 Service Bulletin
Technical Background
To comply with the legal requirements on exhaust gas emissions according to the LEV-1 and LEV-2 standards, a
high exhaust gas quality must be ensured. The necessary catalyst only operates at a temperature over 300°C
(572°F). To achieve this, the catalyst is heated up. The catalyst heating phase is achieved by a late ignition
angles and by introducing additional fresh air to the exhaust valves (secondary air system).
Late ignition angles make sure that the exhaust gas from the cylinders has a higher temperature. This exhaust
gas includes fuel that is un-burnt, and was deliberately injected into great quantities. The secondary air system
adds fresh air to the exhaust gas as it leaves the cylinder and the extra fuel is burnt. As a result, the temperature
of the exhaust gas and of the catalyst increases quickly.
Effects:
The afterburning in the exhaust manifold before catalyst changes the sound characteristic of the engine. This
heating-up of the catalyst, including afterburning, is normal and has no effect on the service life of the engine.
During this catalyst heating phase the engine has increased idle speed, may have increased vibrations, and a
different sound characteristic.
Conditions for the catalyst heating phase:
Depending on conditions the time of the catalyst heating phase varies.

Production Solution
No change

Service
Please do not repair. Explain the technical background to the customer.

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

Page 2 of 3
© 2012 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 Service Bulletin
Additional Information
All parts and service references provided in this TSB are subject to change and/or removal. Always check with
your Parts Department and service manuals for the latest information.

Page 3 of 3
© 2012 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.