Technical Service Bulletin
01 MIL on (P0491 and P0492 stored at same time)
01 13 01 2033001/2 May 29, 2013. Supersedes Technical Service Bulletin Group 01 number 13-83 dated March
29, 2013 for reasons listed below.

Model(s)

Year

VIN Range

Vehicle-Specific Equipment

A6

2009 - 2011

All

CCAA, CALA engines

Audi Q7

2011 - 2012

All

CJWB, CJWE, CJWC engines

A5 Cab

2010 - 2013

All

CCBA engines

A4

2009 - 2011

All

CALA, CCBA engines

Audi Q5

2009 - 2012

All

CALB engines

Condition
REVISION HISTORY
Revision

Date

Purpose

2

-

Revised header data (Added models)
Revised Service (Added information)
Revised Required Parts and Tools (Added part)

1

3/29/2013

Initial publication

• MIL on.
• Both of the following DTCs are stored in the engine control module, J623 (address word 01):
• DTC P0491 (Secondary Air System Insufficient Flow, Bank 1)
• DTC P0492 (Secondary Air System Insufficient Flow, Bank 2)
• Mileage is greater than 15,000 miles.

Technical Background
Under certain driving conditions, the secondary air ports in the cylinder head can accumulate carbon over time,
causing a restriction.

Production Solution
Not applicable.

© 2013 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
Service
Tip: This TSB will be updated soon. Please use the latest revision.
For Audi Q5, S4 and A6 3.0T, follow the steps below. For A6 3.2AVS and Audi Q7 3.0T, call Technical Assistance
Center (TAC). Please note that before performing this repair for the first time, it is mandatory that the technician
complete Audi Academy Course #940134 and assessment #940134B, otherwise the warranty claim will be
denied. The course and assessment can be found on the Audi Academy CRC site. Specific video sections are
reference in the instructions below.
Perform VAS Testing
1. Delete all DTCs and bring the engine to operating temperature.
2. Go into Basic Setting in the VAS tester (VSD) and select Secondary Air System Check.
3. Start the test on the VAS tester.
4. Depress the brake pedal first, followed by the gas pedal.
5. Record MVBs:
PRS_SA_DIF (record max value)
MASS_SA_REL (recode value at the end of test)
• If PRS_SA_DIF max pressure is below 170mbar, follow GFF for these DTCs.
• If max value of PRS_SA_DIF is greater than 170mbar / hPa and MASS_SA_REL below 0.6, the secondary
air ports have to be cleaned. Follow the steps below.
Tip: To restart the test, back out of VSD to the main screen and cycle the key.

Prepare for Power Washing
1. Move the exhaust sliding bushings (that connect the
catalytic converter and muffler) back, then lower the
catalytic converter pipes (Figure 1).
For Q7, unbolt muffler from catalytic converter. Cover
mufflers with plastic bag to prevent water from entering.
Cleaning water will drain out of the catalytic converter
pipes during the cleaning process.

Figure 1. Lowered catalytic converter pipes
© 2013 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
2. Remove all spark plugs and cover the engine harness plugs for the coils (for water protection).
3. Drain the coolant so that it can be reused.
4. Bring front end of the car into service position (for Q5, A6, S4, and S5 Cabrio) to make room in the front of the
engine. The Q7 has enough room for access to the front of the cylinder heads.
5. For 3.0T only: remove the coolant supply lines
(intercooler of supercharger) in the front of the engine
(Figure 2).

Figure 2. Front coolant pipes to be removed for
3.0T
6. Remove the following components:
• Coolant pipe (Figure 3,1)
• Coolant flange (Figure 3,2)
• Pulley and if needed bracket, of power
steering pump (Figure 3,3)
• Pulley of water pump (Figure 3,4)
• Coolant tube (Figure 3,5)
• Dipstick tube (Figure 3,6)

Figure 3. Engine component removal
Note:
When removing the dipstick tube, turn it 180 degrees, then reinstall it for water protection.
© 2013 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
Note:
To loosen the coolant tube, remove 2 bolts (Figure 4, A and C),
open clip (Figure 4, B), and pry bushing apart as shown in training
video (Figure 4, D). There is no need to loosen the AC compressor.
Cover opening of right coolant pipe to prevent coolant circuit
contamination.

Figure 4. Loosening the coolant tube
7. Remove main port freeze plug by hitting
the marked area with a small punch until it
turns (Figure 5). Remove with pliers.

Figure 5. Marked area on main port of freeze plug.

Prepare to Power Wash

Warning:
• Read pressure washer user manual and follow these safety instructions.
• Always insert special cleaning hose into adaptor and engine before turning pressure washer on.
• If switching special cleaning to a different port, turn pressure washer off and release residual pressure by
pulling the trigger before removing the special cleaning hose from the engine.
• Wear safety glasses and gloves.

© 2013 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. Become familiar with the special tool set VAS6825 (Figure 6):
• Special hose with scale for
cleaning single ports (Figure
6,1)
• Special hose for cleaning the
main ports (Figure 6,2)
• Hose adaptor for the special
hose with scale (Figure 6,3)
6 • Engine adaptor for bank one
(Figure 6, 4a)
• Engine adaptor for bank two
(Figure 6, 4b)

Figure 6. Special tool set VAS6825
2. To catch water, put a pan under the front of the engine and under the disconnected catalytic converter pipes.
3. Install engine adaptors on the appropriate banks (Figure 7, Figure 8).

Figure 7. Engine adaptor on bank one.

Figure 8. Engine adaptor on bank two.
© 2013 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
4. To ensure proper pressure washer function, use a ¾-inch water supply hose (no longer than 60 feet) to supply
pressure washer.
The Audi-supplied pressure washer comes with a 22mm male-to-male adapter (to connect special tool to
trigger gun), a pressure gauge (to connect between pressure washer and high pressure hose), and a 220V
power adapter.
Make sure that pressure is at least 1800 psi when using the special single port cleaning hose (the hose with
the scale). Use the table below to compensate for low water pressure:

psi While Cleaning Single Ports

Cleaning Time in Minutes

Less than 1900

Pressure too low – check water supply

1900

4

2000 or higher

3

Power Wash the Ports
Cleaning Main Secondary Port:
1. Insert special main port cleaning hose (the hose without the scale) two inches into the engine adaptor.
2. Turn the pressure washer on.
3. Holding the cleaning hose tightly, pull the pressure washer trigger.
4. Gradually move the cleaning hose into the port, going back and forth until the combi valve is reached. All water
comes out at the adaptor #4.
5. Continue going back and forth through the whole port until only clean water drains out of the cylinder head.
6. Do the same with the other cylinder head.
Cleaning Single Ports:
1. Because every port has a different distance to the cylinder head, use the table below to position the hose
adaptor for the special single port cleaning hose (the hose with the scale) correctly into the hose. The back
side of the hose adaptor must align with the number on the scale of the cylinder to be cleaned (Figure 9). The
longitudinal slot on the hose adaptor must align with the black line on the scale for correct rotational
positioning (Figure 9).

© 2013 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
Dimensions Port

1

2

3

Bank One

10.5

19.5

28.5

Bank Two

13.7

22.7

31.8

Figure 9: Arrow indicating how the back side of the adaptor must align with the scale. Red dotted
line indicating how the longitudinal slot must align with the black line on the scale.

2. After adjusting the position of the hose adaptor, insert the
special single port cleaning hose into the hose adaptor,
and bring it back into locking position (Figure 10).

Figure 10. Locking position / transvers longitudinal
movement and of the hose adaptor
3. While cleaning, make sure that the pressure washer is supplying pressure greater than 1800 psi.
4. Based on the washer’s pressure, clean the port based on the table below. While cleaning, continuously move
the hose adaptor within the longitudinal and transvers slots (Figure 10).

psi While Cleaning Single Ports

Cleaning Time in Minutes

Less than 1900

Pressure too low – check water supply

1900