# ROUGH IDLE



## HIRAM (Feb 15, 2010)

*Hi Guys,

I have a rough idle problem which may be connected with the Air Con system.

The car will idle without any problems then there seems to be a "discharge noise" from the engine compartment like a valve opening to discharge something,  it's intermittent , but if I press the ECON button it stops. [smiley=book2.gif] I've ran a VCDS-VAGCOM (908.2) but no faults, any "Ologists" any ideas (TT 1.8t quattro 1999 5spd 180 AJQ*)

Best Regards Rob


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## T3RBO (Dec 9, 2003)

Welcome to the forum 

Try posting the question in the mk1 section for a wider audience :wink:


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## Black BeTTy (Apr 14, 2010)

check your maf sensor.. 9 time out of 10 rough idle is mass air flow sensor... good luck hope this helps


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## HIRAM (Feb 15, 2010)

*Thankx for the reply I really do appreciate it, 

but some how it's linked with the air con system that I'm sure of because when I activate the econ button that turns off the air con system, then when I re-engage the air con system by pressing the button again the same intermittent rough idle happens .

I have also tried different permutations of disconnecting the a/c pressure switch and also the electrical connection on top of the a/c unit, result: if there is no power to a/c unit -smooth idle, I don't have enough tech-info to make a proper investigation. The above account was all try and error today* [smiley=bigcry.gif]


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## ahaydock (Sep 19, 2006)

Hello and welcome along to TTF


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## HIRAM (Feb 15, 2010)

Thanks for the welcome to the forum,

I was expecting more input from"probably the worlds greatest TT resource" with my problem 

does anyone have wiring diagram & component circuit of the air con system, As the VCDS/ vag-com shows no faults is the a/c the cause of the problem or is it the effect from another? VCDS/vag-com tells me that the a/c clutch is operating ok

Best Regards Rob[/b]

Chassis Type: 8N - Audi TT
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AJQ.lbl
Part No: 8N0 906 018 AC
Component: 1.8L R4/5VT 0002 
Coding: 05700
Shop #: WSC 06435

No fault code found.
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8N0-907-379-MK20-E.lbl
Part No: 8N0 907 379 E
Component: ESP 20 CAN V005 
Coding: 18446
Shop #: WSC 00383

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: None
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03 
Coding: 00041
Shop #: WSC 00088

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: None
Part No: 8N8 909 601 
Component: Airbag Front+Seite 0005 
Coding: 10102
Shop #: WSC 06435

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: Redir Fail!
Part No: 8N2 919 930 B
Component: KOMBI+WEGFAHRS. M73 D30 
Coding: 04444
Shop #: WSC 00050

Part No: Ident
Component: Nr. Wegfahrs.:AUZ5Z0F4235037 
Ident.-Nr. Wegfahrs.:AUZ5Z0F4235037

No fault code found.

-------------------------------------------------------------------------------
Address 22: AWD Labels: 
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006

No Faults Found
or DTCs not supported by controller
or a communication error occurred

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: 8Nx-962-267.lbl
Part No: 8N8 962 267 B
Component: Central Lock/Alarm D04 
Coding: 04810
Shop #: WSC 00383

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N8 951 177 
Component: Innenraumueberw. D09 
Coding: 00001
Shop #: WSC 00000

No fault code found.

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4B0-907-357-AUT.lbl
Part No: 4B0 907 357 
Component: LEUCHTWEITEREGLER D003 
Coding: 00010
Shop #: WSC 06435

No fault code found.

End ---------------------------------------------------------------------
Monday,03,May,2010,17:40:37:28026
VCDS Version: Release 908.2
Data version: 20100326

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][/b]


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## Jamo8 (Apr 23, 2009)

HIRAM as said previously post this in the MK1 section and you will get the answers you are looking for,not many users browse the Welcome New Users section


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