Technical Bulletin
Model(s)

Year(s)

Eng. Code(s)

Trans. Code(s)

VIN Range From

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2018

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Condition
87 17 13 November 9, 2017 2049039
Air Conditioning, Cleaning of the Refrigerant Circuit with R1234yf (U.S. Only)
Debris can be dispersed throughout the refrigerant circuit after A/C component damage. In order to maintain A/C
operating efficiency, it is important to flush the refrigerant circuit after A/C component repairs.
Note:
This bulletin must be read in its entirety before beginning repair.

Technical Background
In cases where an air conditioning system component (such as a compressor or other system component has
failed and debris from the compressor or component is circulated throughout the refrigerant circuit, the refrigerant
circuit must be cleaned of any and all debris or damage to the replacement components will result.

Production Solution
No production change required.

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© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
Service
Tools
Use the MAHLE R1234yf A/C Service Unit VAS581005 and
the R1234yf Flush Kit RTI360831040 (Figure 1).
Used for effective refrigerant handling and air conditioning
circuit flushing after air conditioning component failure.

Figure 1. The VAS581005 Air Conditioning
Service System with Flushing Device.

The VAS 6338/1 Adapter Set for Refrigerant Circuits along with an additional adapter VAS 6338/38 for the
expansion valve bypass this kit, contains the adapters necessary to complete a thorough flush operation of a
contaminated circuit.
Elsa contains the technical information for each model regarding the necessary adapter applications
and connections of the servicing station for the flush operation. See Heating, Ventilation & Air
Conditioning >> Refrigerant R1234yf-Servicing >> 00 General Technical Data>> Refrigerant Circuit
removing contaminates>> Refrigerant Circuit, Flushing with Refrigerant R1234yf in Elsa.
All other refrigerant recovery, evacuation and recharge operations are performed using the usual procedure
specified in Elsa. An operations manual will accompany each servicing station that will describe operation of
the unit.

Page 2 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
Procedure
Front A/C:
1. If an air conditioning component has been diagnosed as the root cause of the failure, and this particular
component has been verified to have released debris through the circuit, continue with the flush procedure.
2. Switch the power to the servicing station ON and begin by recovering the refrigerant from the system through
the normal service fittings.

Note:
For all compressor replacements it is mandatory to flush the system of all oil in the system. The
replacement compressor comes with a full charge of oil for a complete A/C system.

Tip:
During the entire process avoid interrupting the power to the station. The station's internal memory will keep a log
of all operations and can conveniently be recalled and printed. If the power is interrupted, the station will lose the
memory of the process, and the oil volume recovered, oil volume added, refrigerant volume recovered, etc. will
have to be manually determined.

3. Disconnect the service hoses from the AC service ports of the refrigerant circuit.
The VAS 6338/1 adapters will be used to bypass the following:
 Compressor.
 Expansion Valve.
 Rear AC lines to rear AC unit (If Equipped)
 Rear AC unit Expansion Valve (If Equipped)

Note:
For models with receiver drier desiccant cartridge the desiccant cartridge must be removed for the flushing
process.
For vehicles where the receiver drier is located on the condenser and DOES NOT have a remove-able desiccant
cartridge, the receiver drier must be left in the system and flushed through.
After the flush procedure is complete replace the receiver drier or drier cartridge.

4. Installing the R1234yf Flush Kit RTI360831040 flush tank to the Mahle A/C Service Unit VAS581005
5. Remove Receiver Drier. Refer to Elsa Repair Manual.
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© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
Note:
For Atlas, the front bumper does not need to be removed as stated in the Elsa repair manual.
When removing front grille ensure ignition is switched OFF and negative battery cable is disconnected
before disconnecting the front distance regulation module.
6. Remove receiver drier cartridge.
Reinstall cartridge cap with O-ring.
(Figure 2)

Figure 2, Location of the Receiver Drier

7. Remove expansion valve and install flush plate VAS
6338/38. (Figure 3)

Figure 3 Installation of front expansion valve bypass
adaptor VAS 6338/38.

Page 4 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
Note: (Atlas Only) The rear A/C unit refrigerant
lines must be disconnected and replaced with block off
adaptors VAS 6338/5 and VAS 6338/63 before
performing the front A/C unit flush procedure.
8. (Atlas Only) Disconnect rear refrigerant lines and
install adaptors VAS 6338/5 and VAS 6338/63 as
shown. (Figure 4a, 4b)

Figure 4a. Installation of high side rear A/C Line
connection block adaptor VAS 6338/63

Figure 4b Installation of Low side rear A/C Line
connection block adaptor VAS 6338/5

Page 5 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
9. Remove A/C Recovery machine high side coupler
from hose.
Install flush adaptor VAS 6338/48 to high side A/C
recovery machine hose. (Figure 5)
Note: You do not have to remove low side A/C
hose coupler. The low side coupler will be connected to
the flush tank filter adaptor.

Figure 5. A.C hose adaptor 6338/44

10. Disconnect AC compressor hoses from the
compressor.
Install flush adaptor VAS 6338/3 on the high side
compressor hose.
Install flush adaptor VAS 6338/12 on low side
compressor hose. (Figure 6)

Figure 6. Installation of VAS 6338/3 and 6338/12.

Page 6 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
11. Attach high side A/C Recovery machine hose with
VAS 6338/48 fitting to low side compressor hose
adaptor VAS 6338/12 (Figure 7)

Note: This connection strategy allows for a system
flush in the opposite direction of the normal refrigerant
flow.

Figure 7

12. Connect the low side A/C machine coupler to the
flush tank filter adaptor. (Figure 8)

Figure 8

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© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
13. Connect flush tank hose (Yellow) to the high side
compressor hose adaptor VAS 6338/3. (Figure 9)

Figure 9

14 Perform an extended 3 cycle flush.
15. After the flush process completes remove any adapters that were installed from the VAS 6338/1.
16. (Atlas Only) Proceed to section for cleaning the rear A/C unit. All others models continue to step 17.
17. Install a new Expansion Valve and Receiver Drier Cartridge. Reassemble all refrigerant lines.
18. Print the extended flush log of the job and attach to the repair order.
19. Connect the station in the usual manner through the service fittings and perform the normal evacuation and
refrigerant recharge operations.
Note: For Atlas a rear A/C unit flush must be performed before vacuum testing and recharging.

Atlas Rear A/C Unit
The flush process will be repeated for the additional rear air conditioning unit according to the repair information in
Elsa.

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© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
20. Lower the exhaust buy removing the rear exhaust
clamp and single rubber hanger. (Figure 10)

Figure 10

21. Remove the cross bar located in the center under
carriage area. (Figure 11)

Figure 11
Page 9 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
22. Remove middle heat shield from under previously
removed cross bar to access rear expansion valve.
(Figure 12)
Note: Replace the clamping washer before
reinstalling the heat shield.

Figure 12

23. Remove rear expansion valve and install
VAS6338/38 as shown. (Figure 13)

Figure 13. Location of rear air conditioning unit
expansion valve.

Page 10 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
24. Connect the VAS 6338/3 and VAS 6338/60 to the
rear refrigerant A/C lines previous disconnected in step
12. (Figure 14)

Figure 14. Location and connection of the adaptors for
the rear unit A/C lines

Page 11 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
25. Connect the VAS 6338/3 and VAS 6338/60 to the
rear refrigerant A/C lines.
26. Connect the VAS 6338/44 to adaptor VAS 6338/60
27. Connect flush tank hose (Yellow) to the high side
compressor hose adaptor VAS 6338/3. (Figure10)
Note: Reverse flushing not required for rear A/C
unit cleaning.

Figure 10. Attaching service station and flush hoses to
rear A/C lines.

28. Perform an extended 3 cycle flush on the rear A/C unit.
29. When complete, remove any adapters that were installed from the VAS 6338/1.
30. Install a new rear Expansion Valve and reinstall all the refrigerant lines.
31. Connect the station in the usual manner through the service fittings and perform the normal evacuation and
refrigerant recharge operations.
32. Print the extended flush log of the job and attach to the repair order.
33. Connect the station in the usual manner through the service fittings and perform the normal evacuation and
refrigerant recharge operations

Page 12 of 19
© 2017 Volkswagen Group 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 Volkswagen Group 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 Bulletin
A/C Components Replacement
The following components must be replaced:
 Expansion Valve
 Rear Expansion Valve (If equipped)
 Receiver-drier/cartridge

Warranty

Note: