# 01 Audi TT 225 New owner Q's - Keys, VagCom, Parts & Service



## TheSchwartz (Sep 3, 2014)

*01 Audi TT 225 New owner Q's - Engine knock*

Happy to say that yesterday i purchased a 2001 Audi TT 225 Coupe in silver w/ 103k on the clock! It was a long process finding the right car and now I would like to keep it happy for a long time. I haven't gotten any time to really get deep into the bits and bobbles of the car yet but there are a few things that I would like to get taken care of right off. I do have a fair bit of wrench turning experience and feel very confident and comfortable working on my own cars. For starters lets get a list of all the gen-maint items that I have on the way already (Im a quick start!) 

-ECS Ulitmate Plus timing belt kit (belt, pump, thermo, thermo housing, tensioner, pulley, coolant, misc gaskets)
-Coolant after run pump (smelled faint coolant smell figured I would get this out of the way)
-Coolant Flange (again smelled coolant, might as well do it while im in there)
-Valve cover gasket set (leaking, also got cap gasket cause its bad m'kay)
-710N Diverter valve (who knows how old the one on the car is)
-Brake pad set (cause stopping is the most important function of your car)
-Hazard switch/relay (turn signals intermittent failure, works when tapping dash)
-Oil change (used Mobile1 0-40 for European cars Bosch filter)
-Cabin filter, charcoal (cause no one wants a nose full of funk)
-Washer fluid cap (keeps the juice in)
-Coolant reservoir (stock one looks like poo)


Now thats out of the way I fully expect someone to come along and kick me in the pants for getting the wrong stuff but, Hey, Im down to hear Im wrong once in a while! Now on to the questions, I have done some surfing on these Q's but haven't come up with any definitive answers so I figured I would come here and drop them off for your personal enjoyment. 


-Coolant fans
I dont think its working properly. The needle makes its way to the middle, pretty normal, then it wants to wander between half and 3/4 on the hot side. Im pretty sure this isnt normal. I know my way around a multimeter and will get at it this afternoon, I will get the fan itself checked and the fuses, anything else to look at?

-A/C not working
Usually this isn't a question I would ask but it sounds like the compressor is kicking on but im not getting any cold air? Again I will take a closer look this afternoon but any ideas on why I would get a relay click from under the hood when I turn on the *fan, heater, set to "LO" whatever-u-wanna-call-it, with the swooshy arrow lit but nothing else*?

-VagCom for Dummies
There is so much info out there about VagCom that it has become overwhelming. I would like to be able to diagnose problems with the car, thats about it unless someone can convince me that there is more I should be doing with it. I dont want to spend a ton here, cheap but functional

-Key Replacement
The car only came with one key, not a good thing for me cause i misplace stuff regularly. Audi quoted me at 300ish for one key, insane! Im sure someone in the area will cut the key for less, I have read about programing the remote, but what about the immobilizer. is VagCom an answer?

-Ecu Tuning
How ever would you know if your car was tuned? It has an exhaust (Magnaflow) I think the stock downpipe and cat are still there, sounds good but not loud. Shift knob has been changed (garbage B&M, cant say enough bad about this jank job, getting a stock one) Car had a stereo. Has stock intake and intercooler setup, some "performance" filter (changed back to stock paper) All signs of a car that has been modified, just wondering how far they went.

-Dash LCD Display
Oh yeah, its bad. Looks like my German car is trying to communicate in Japanese. Dunno about the rest of the dash, seems to work. Who does this fix for a good price with good results? Any chance of striping the cluster down myself, purchasing a display on ewwBay, and taking the board and display to an electronics shop or is there more to it than that?

-Boost Gauge
I hate to type it let alone install one. I know they can help with diagnosing engine problems, but I think they look bad, so I would like one but Im looking for something very stealth or stock looking. Def not willing to give up a vent for one!

Any and all help is appreciated.

>Michael


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## hermes350GT (Oct 18, 2013)

I have the awe vent boost gauge on the driver side left of the steering wheel. The nice thing about this one is the vent still functions.


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## hunTTsvegas (Aug 27, 2012)

TheSchwartz said:


> Happy to say that yesterday i purchased a 2001 Audi TT 225 Coupe in silver w/ 103k on the clock! It was a long process finding the right car and now I would like to keep it happy for a long time. I haven't gotten any time to really get deep into the bits and bobbles of the car yet but there are a few things that I would like to get taken care of right off. I do have a fair bit of wrench turning experience and feel very confident and comfortable working on my own cars. For starters lets get a list of all the gen-maint items that I have on the way already (Im a quick start!)
> 
> -ECS Ulitmate Plus timing belt kit (belt, pump, thermo, thermo housing, tensioner, pulley, coolant, misc gaskets)
> -Coolant after run pump (smelled faint coolant smell figured I would get this out of the way)
> ...



Michael,

Welcome to the esteemed MKI TT owners club. This car has the possibility to be the best thing you've ever owned or make child support look like lunch money. A few things: 

1) The engine temp guage could be related to the cluster going bad. Your fans and coolant system COULD be functioning properly. Either way, if you're looking to get the LCD updated then you may as well have the whole cluster rebuilt and updated with some quality components. I've been working recently with  Speedo Solutions and have heard nothing but great things from them. His service offers an extremely quick turn around.

2) Definitely not one to insult anyone's intelligence but the first thing I would check would be is Freon. Depending on how the levels look may tell you exactly what's going on. Is air coming out of the vent, it's just not cold?

3) Vag com is pretty straight forward but HERE is a good place to start. To group boost gauge with this area: if you don't want a boost gauge in a vent (even though there are adapters that still provide sufficient airflow) then you have the option of using VCDS/Ross Tech for real time data logging or find an OSIR Gauge pod like THIS and modifying it to take place of the ashtray. Logging boost request plus actual with VCDS/Ross Tech will also tell you if you have an ecu that has been "tuned" because the pressures will be higher than stock pressures. This isn't a necessarily a bad thing if it's just stage 1 as most have a tendency to increase fuel efficiency provided you can stay out of the throttle.

4) Key replacement, I'll let someone else chime in on. I have yet to do it. If there is no definitive answer then it may just be safer to go with the "stealership" and their extremely inflated price but I don't see why there isn't a possibility of coding an additional key with VCDS/Ross Tech. 

Again, welcome to the family! :beer::beer:


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## TheSchwartz (Sep 3, 2014)

So I made my way over to Ross Tech and got the vagcom kit for the TT on order. I also spent some time with my nose under the hood. I kinda feel like it was one step forward and two steps back. Here are my findings

Neither fan will engage on its own, the interior fan must be on and then BOTH fans will run. Sensor? Any help here, seriously, I dont want to kill my new toy!

The a/c pump is engaging, but it is not producing cold air. I suspect that the system is just low on freon, I will get my gauge set out tomorrow and check the pressure in the system. Any other suggestions?

The wipers will work but the washers will not. I thought it was just out of fluid but I cannot seem to get the pump to make any noise. I intend to check the relay, which one is it?

>Michael


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## ssweetd (Jan 17, 2006)

*Haldex*

Should also change Haldex fluid and filter.

Enjoy the car! :thumbup:


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## TheSchwartz (Sep 3, 2014)

I will be ordering the Haldex fluid, filter, and tool from ECS in the next day or two. How about the rear end and transmission? I have always used Amsoil in my 240sx, really only once cause its good for 100k miles. 

Anyone using Amsoil in their Audi? 

Anyone care to add to the list of general maintenance items? 

Any help on that funky radiator fan?

>Michael


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## hunTTsvegas (Aug 27, 2012)

TheSchwartz said:


> So I made my way over to Ross Tech and got the vagcom kit for the TT on order. I also spent some time with my nose under the hood. I kinda feel like it was one step forward and two steps back. Here are my findings
> 
> Neither fan will engage on its own, the interior fan must be on and then BOTH fans will run. Sensor? Any help here, seriously, I dont want to kill my new toy!
> 
> ...


Micheal,

I forgot to also add that a Bentley manual can definitely be your best friend. I'm also trying to search some of the threads I'm following as I'm pretty sure that the fan issue has been covered in detail by one of the more knowledgeable guys here. 

Only reason I asked whether air was blowing in the car or not is to gauge if the servo motor behind the dash was activating to allow airflow in the car. Aside from that, there's not much to the AC system. Condensor, pressure switch, temp sensor, receiver/drier, expansion valve and evaporator. Again, difficult to diagnose without having a refrigerant manifold hooked up checking both the high and low pressure sides. 

As far as the washer pump, I'm not sure of the exact relay but the easiest way to access the pump itself is behind the drivers side front fender liner. I had a similar problem and it turned out that the actual plug was disconnected by the previous owner for some reason.



TheSchwartz said:


> I will be ordering the Haldex fluid, filter, and tool from ECS in the next day or two. How about the rear end and transmission? I have always used Amsoil in my 240sx, really only once cause its good for 100k miles.
> 
> Anyone using Amsoil in their Audi?
> 
> ...


Also, can't speak for Amsoil but I use Redline fluids for the rear end and transmission and they seem to work great as an alternative to the factory fluids (Synthetic 75w90 gear oil). 

:beer:


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## TheSchwartz (Sep 3, 2014)

Im gonna hafta call my Amsoil rep and see what he says. 

Thanks for all the help so far, I really appreciate it. 

I had intended on getting the manual for the Audi but I haven't had time to look into it yet. I was really hoping to find one online, anyone know if its available for download?

I had thought about looking at the plug, for whatever reason I get the feeling that it may be unplugged. Just seems like an odd part to have expire with the infrequency of use. 

The air definitely blows in the cabin, it seems just a bit cooler than ambient temps which also has me leaning toward low freon level. Just before I pulled off the lot the salesman looked at me and said "Don't turn off the fan, it will turn off the fan" it wasnt until the car started getting warm that I realized what the heck it was he was talking about. I could have poked him in the eye when it dawned on me. 

>Michael


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## bass 1 (Jun 11, 2013)

cooling fans - im still troubleshooting a similar problem, but at least one of my fans seems to work normal. There are the standard fuses and temp sensors, but also check out the fan control module....they are notorious for causing issues similar to what you describe

LCD disp - I just got mine back from modulemaster, very quick turnaround time as well and awesome customer service. Not cheap tho. Boost gauge related, ive seen people remove the center plate in the gauge cluster (sometimes a microphone) and have a small digital display for boost. Might be too much work, but worth looking into since you don't like the visual aspects of an aftermarket gauge. I have the AWE vent gauge which allows airflow around it, but i would say that vent's airflow is reduced ~50% after the install.

AC - As others suggested, check the easy things first (freon levels). In my case, the compressor kicked on and did A LITTLE work, but I was told the high side wasnt high enough and the lows werent low enough. Basically the compressor didnt totally crap out, but enough to not make cold air.

ECU tuning - I would guess that any ECU tune would increase boost levels. Stock should be around 12psi. Also i think most ECU flash companies slap a "do not remove" tamper seal on the outside of the ECU for warranty purposes.... those two things are the quick and easy checks for upgrades.


Hope you are able to start enjoying your new car!


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## TheSchwartz (Sep 3, 2014)

So this morning I noticed a new issue. I believe its the traction control, There is a light on the cluster, a circled arrow with a triangle exclamation point in the center. It came on last night and now wont go off. I get a binding noise from under the car when i turn the wheel tight.

Im ready for my VagCom cable now!

>Michael


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## ssweetd (Jan 17, 2006)

Your Haldex controller could be disconnected, or failing/failed. Check the plug to make sure it is tight.

The binding - if it is the controller, it may be failed in a way that is causing the Haldex to be engaged and keeping the diff locked.

I think you may see that light with an ABS issue, but I do not think it will cause the binding issue. Could be wrong. Keep us updated.


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## TheSchwartz (Sep 3, 2014)

So it seems like the binding is only when its cold. After running some errands and spending some time at the shop I noticed when I parked it that there was no noise.
How common is a Haldex failure?

I checked the A/C system for freon. The low side seemed a bit high but the compressor is running non stop, causing a slight quiver in the gauge. I believe the compressor is bad and someone overfilled the system trying to get it to work as a cheap fix.

Ross Tech sent me an email today notifying me that they overnighted the VagCom kit I ordered, should be here by 10:30am! So long as the product is as good as the ordering and shipping process has been I will be very impressed. Looking forward to putting it to use.

Didn't get a chance to look at the fan control module, found a guide to test it. Hopefully with the guide and the VagCom I can get it rooted out. I need the fans to work properly so that I can fix the A/C. Im afraid that if I have the freon drained to replace the compressor that the fans will stop working when the ecu shuts down the A/C system for low pressure. 

Found a weird aluminum hose connector that looks less than stock, any clues why its there?

Got plates, polished headlights.

And now.......Pictures!










Excuse my dirty interior / car. I have yet to clean her up, but its coming.










Clear eyes.










Mystery mod.










Yes, I have all the engine bay covers, just not on right now. 

>Michael


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## Boulderhead (Oct 21, 2012)

VCDS pays for itself very quickly, and you will be happy that tool is only a few clicks away once you get it. That metal piece you have is definitely some home engineering which is only linking the two pieces of rubber it dives into (assuming its not a valve).

Most of us delete that N249 assembly (meant to open the DV when there isn't enough natural vacuum) and run straight off the manifold to simply things and clean up the engine bay. There are a number of topics on deleted all emissions, but personally that is the only component i dropped as I have to pass emissions every year and don't have the readiness tuned to always be set to On.


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## ssweetd (Jan 17, 2006)

Looks good! I love the cloth seats - have not seen them before in a TT.

The Haldex discussion is like opening Pandora's box.

These cars should not bind at all for any reason. My belief is that there are a lot of TT's out there with Haldex issues, for different reasons, and people do not realize it. Quattro still works though, and may continue to work fine as long as you are not making lock to lock turns.

There are four parts to that system - the controller, the 'cargo pump', the Haldex, and the rear diff. I think controllers fail mechanically, or pumps fail, and there are no codes thrown. Due to that, after a while, with the Haldex always engaged, the Haldex eventually begins to fail. If a controller fails electrically, then you will see a code.

Dealerships do not see enough of these cars and their issues to know how to troubleshoot properly, and they will not repair the parts individually.

I think non-enthusiasts probably buy these cars used, take them to their local garages, and have no idea that the Haldex fluid needs to be changed every 20k, and the Haldex filter every 40k. Or that the front transaxle, Haldex diff, and rear diff, all use different fluids.

These are just my opinions based on my own Haldex saga! 

Oh, one more thing - if you have a Bose system, you cannot fade to the rear, even though you have the option on the stereo. It is designed that way by the Bose engineers. You still have lows from the rear. The rest of the sound is in the doors, and a speaker in the center of the top of the dash.


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## TheSchwartz (Sep 3, 2014)

Im quite interested in this "Pandora's Box". Im a bit O.C.D. when it comes to mechanical workings and seeing them function properly. If its not supposed to make noise, which Im fairly sure its not, then it must be broken and therefore fixed. It is, however, a secondary issue at the moment. I was only asking because of its relation to the dash light, which is burning a hole in my brain. 

Unfortunately I dont have the factory stereo, kinda wish I did, I will deal with the stereo another day 

Yeah, I dig the seats too. I really dont like leather, especially in this southern heat. A friend of mine cleans carpets for a living and his opinion was that they look like they will clean up nice, Im totally stoked about them. 

>Michael


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## TheSchwartz (Sep 3, 2014)

Alright, so I took the the codes from the ECU and came up with a few different codes. 

This scan done right outta the box, engine off, key on

Tuesday,30,September,2014,15:09:10:16235
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.3.0 (x64)
Data version: 20140905


Mileage: 166170km-103253mi Repair Order: Mikes/1



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8N - Audi TT (1999 > 2007)
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Mileage: 166170km/103253miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AMU.lbl
Part No: 8N0 906 018 AT
Component: 1.8L R4/5VT G 0003 
Coding: 06710
Shop #: WSC 00000 
VCID: 830B07EC912AF30606F-5178

6 Faults Found:
16486 - Mass Air Flow Sensor (G70) 
P0102 - 35-00 - Signal too Low
16518 - Oxygen (Lambda) Sensor B1 S1 
P0134 - 35-10 - No Activity - Intermittent
17965 - Charge Pressure Control 
P1557 - 35-10 - Positive Deviation - Intermittent
17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) 
P1297 - 35-10 - - Intermittent
17545 - Fuel Trim: Bank 1 (Add) 
P1137 - 35-00 - System too Rich
17521 - Oxygen (Lambda) Sensor; B1 S1 
P1113 - 35-10 - Internal Resistance too High - Intermittent
Readiness: 0010 1001

-------------------------------------------------------------------------------
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 01236 
VCID: 3E7D36183A48DEEEA91-4B18

2 Faults Found:
01314 - Engine Control Module 
79-00 - Please Check Fault Codes
01324 - Control Module for All Wheel Drive (J492) 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03 
Coding: 00140
Shop #: WSC 01236 
VCID: 2851F040C8CC705EF3D-2592

1 Fault Found:
00604 - Potentiometer Positioning Motor for Air Flow Flap (G113) 
30-10 - Open or Short to Plus - Intermittent

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8N8-909-601.lbl
Part No: 8N8 909 601 
Component: Airbag Front+Seite 1008 
Coding: 10102
Shop #: WSC 01236 
VCID: F7F3633CD5F2AFA62A7-5178

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Nx-920-xxx-17.lbl
Part No: 8N1 920 930 E
Component: KOMBI+WEGFAHRS. M73 D08 
Coding: 07244
Shop #: WSC 00000 
VCID: 336B172C010A038656F-4B32

No fault code found.

-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006 
VCID: 1F43EB9C9D82B7E6827-4B18

No fault code found.

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: None
Part No: 8N
Component: Zentralverrieg. D04 
Coding: 00000
Shop #: WSC 00000 
VCID: 860D1EF8A218C62E211-4F02

3 Faults Found:
01570 - Turn-Off Delay; Terminal 15 
29-10 - Short to Ground - Intermittent
01559 - Drivers Door 
61-00 - Won't De-Safe
01560 - Passenger Door 
61-00 - Won't De-Safe

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N8 951 177 
Component: Innenraumueberw. D09 
Coding: 00001
Shop #: WSC 00000 
VCID: FCF97C10ECD48CFE475-5196

1 Fault Found:
01462 - Anti-theft alarm ultra sonic Sensor (G209) 
53-00 - Supply Voltage Too Low

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4B0-907-357-AUT.lbl
Part No: 4B0 907 357 
Component: LEUCHTWEITEREGLER D004 
Coding: 00010
Shop #: WSC 01236 
VCID: E5CF39747F5E2D3688B-51D0

No fault code found.

End --------------------------------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Then I ran the codes with the engine running and everything was the same except this

Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006 
VCID: 1F43EB9C9D82B7E6827-4B18

2 Faults Found:
01316 - ABS Control Module 
49-10 - No Communications - Intermittent
01314 - Engine Control Module 
49-10 - No Communications - Intermittent


Then the codes were cleared and re read, these codes came back immediately

-------------------------------------------------------------------------------
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 01236 
VCID: 3E7D36183A48DEEEA91-4B32

2 Faults Found:
01314 - Engine Control Module 
79-00 - Please Check Fault Codes
01324 - Control Module for All Wheel Drive (J492) 
49-00 - No Communications

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006 
VCID: 1F43EB9C9D82B7E6827-4B18

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

-------------------------------------------------------------------------------

After that the codes were again cleared and the car was taken for a drive ~ 15min 
then scanned again

Tuesday,30,September,2014,15:52:42:16235
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.3.0 (x64)
Data version: 20140905


Mileage: 166180km-103259mi Repair Order: mikes-4



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8N - Audi TT (1999 > 2007)
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Mileage: 166180km/103259miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AMU.lbl
Part No: 8N0 906 018 AT
Component: 1.8L R4/5VT G 0003 
Coding: 06710
Shop #: WSC 00000 
VCID: 830B07EC912AF30606F-515A

2 Faults Found:
16486 - Mass Air Flow Sensor (G70) 
P0102 - 35-00 - Signal too Low
17521 - Oxygen (Lambda) Sensor; B1 S1 
P1113 - 35-10 - Internal Resistance too High - Intermittent
Readiness: 0010 1101

-------------------------------------------------------------------------------
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 01236 
VCID: 3E7D36183A48DEEEA91-4B32

2 Faults Found:
01314 - Engine Control Module 
79-00 - Please Check Fault Codes
01324 - Control Module for All Wheel Drive (J492) 
49-00 - No Communications

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03 
Coding: 00140
Shop #: WSC 01236 
VCID: 2851F040C8CC705EF3D-2592

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8N8-909-601.lbl
Part No: 8N8 909 601 
Component: Airbag Front+Seite 1008 
Coding: 10102
Shop #: WSC 01236 
VCID: F7F3633CD5F2AFA62A7-5178

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Nx-920-xxx-17.lbl
Part No: 8N1 920 930 E
Component: KOMBI+WEGFAHRS. M73 D08 
Coding: 07244
Shop #: WSC 00000 
VCID: 336B172C010A038656F-4B18

No fault code found.

-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006 
VCID: 1F43EB9C9D82B7E6827-4B18

2 Faults Found:
01316 - ABS Control Module 
49-10 - No Communications - Intermittent
01314 - Engine Control Module 
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: None
Part No: 8N
Component: Zentralverrieg. D04 
Coding: 00000
Shop #: WSC 00000 
VCID: 860D1EF8A218C62E211-4F1E

2 Faults Found:
01559 - Drivers Door 
61-00 - Won't De-Safe
01560 - Passenger Door 
61-00 - Won't De-Safe

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N8 951 177 
Component: Innenraumueberw. D09 
Coding: 00001
Shop #: WSC 00000 
VCID: FCF97C10ECD48CFE475-5196

No fault code found.

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4B0-907-357-AUT.lbl
Part No: 4B0 907 357 
Component: LEUCHTWEITEREGLER D004 
Coding: 00010
Shop #: WSC 01236 
VCID: E5CF39747F5E2D3688B-51D0

No fault code found.

End ---------------------------------------------------------------------


So it looks like I have codes for the: MAFS, o2, DV, ECU Comms, AWD Comms, Air Flow Flap, Turn off delay, Doors, Anti Theft Alarm voltage. 

The ones I will be asking about are: ECU Comms, AWD Comms, Air Flow Flap. 
The rest seem like they are pretty self explanatory, however, Im always open to suggestions. 

Sorry for the massive post, I probably will not post entire scans again, just the first time so you can see what I see

>Michael


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## TheSchwartz (Sep 3, 2014)

I dont like how quiet it got here. 

I found a very good price on a used but known good mafs, direct replacement o2, and a new fan controller. I didnt want to go thru all the trouble of removing the controller to test it, just to have to put it back while I order a new one. 

After some research I found that some people with similar problems are blaming it on the dash being completely knackered, a wet ecu, or faulty wiring. Currently my dash computer believes its alwyas 72 outside (I wish) and that Im always averaging 21mph (LIES!) So I have contacted SpeedoSolutions about having it rebuild and will hopefully get it sent out tomorrow. 

I have a new cabin filter coming with the box of goodies from ECS so I will look at the ecu while im there. Can you swap an ecu with VagCom?

Next up is the wiring "I ain't skerrd" Been down this road before with the 240, 25years of neglect on that car and not a single faulty wire. I fully expect the same experience, bad plug pins, corroded junctions, and simply disconnected wiring. I will grab some Deoxit D5 later today, if you haven't used it before you should really check it out. 

I need a copy of the wiring junction diagram for this car. Usually they show all the wire plug junctions and name the connectors. I have ordered a copy of Elsawin but it will be a few days before it arrives, any help is appreciated. 

If you have any other ideas of where to look for the solution to my issues, speak up. I promise I wont get mad if you tell me I'm screwed, I may however disagree!

>Michael


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## ssweetd (Jan 17, 2006)

You're making good progress!

I'm of no help with the particular VAGCom codes you are showing. I have a generic cable that I use to see what codes may come up on ours, but so far, we've been relatively lucky and have not had to deal with too much.

You might get more answers if you cross post those results on the VAGCom forum on here.

The only wiring issue we ever had with our 2003 225Q was the 'stuff' that sits on top of the battery. It was something related to the AC and not allowing the compressor to come on, so the dealer replaced that assembly.


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## TheSchwartz (Sep 3, 2014)

Well I'm sure you hafta be thinking I'm either personally wealthy (I wish) or that I am some rich kid (NOT!) but, truth be told, I was in a motorcycle accident December of last year and it looks like I have a few more months before they release me back to work. Due to the fact that my bike was my daily I now am forced to have this car completely road ready by no later than December 15th, or burn it and get something else. I like the first option better. So this afternoon I will be renting another storage unit and housing the Audi there until I can finish with the dash, timing belt, fan relay, o2, mafs, brake pads, head cover gasket, thermostat, coolant flange, dv, maybe the A/C, and hopefully whatever is wrong with the wiring. Then its gonna get a serious bath, that is one dirty pig!

I will hit up the VagCom forum later this evening. I also found that Ross-Tech has a listing of alot of the VagCom codes and their descriptions on their website. A very good resource. Oh and I totally suggest getting the Ross-Tech kit any way you can. I have used everything from Snap-on scanners to eBay Comm Cables and this thing is, without a doubt, the very best piece of kit I have ever had the pleasure of using. Its simple enough to just plug it in and scan for codes and complicated enough that you could seriously damage your vehicle, and they separated the sections into "Safe" and "READ THE MANUAL" which I love. Also if your in the NOLA area and need to use the cable just lemme know!

>Michael

PS: Yes there will be pictures, LOTS of them!


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## TheSchwartz (Sep 3, 2014)

So I have been working on this for the last few days now. So far I have the timing belt/water pump, DV, thermostat, coolant 12v pump, fan control module, cabin filter, hazard switch, o2, and coolant flange done. YAY! BTW they were all stock original with manufacturing codes of 00, same year the car was made!

Found my coolant leak. It was the o-ring that goes on the coolant temperature sensor. $0.69! gotta love NAPA!

Hopefully the gauge cluster is somewhere outside Chicago in some state of dis-assembly and repair. 

I have been checking connectors everywhere on the car. ECU, fine; CCM, fine; ABS, fine; Door harnesses, fine. There is no sign of any kind of water intrusion, corrosion, or discoloration on any of the parts that I have seen. The only things that I have found so far that are electrically alarming are the horrible radio install, and the fact that the Bose amp is unplugged. 

Anyone know if the amp is ok being unplugged or whats the hurt in plugging it in? FWIW the speakers have all been wired individually, independent from the vehicles original stereo. Just wanna know before I put the interior back in the car. 

Also, I have seen the guides on the interwebs about the "Alarm Module" and its dead batteries causing all kinds of havoc and set about finding mine, with no luck. can anyone clue me in about this mythical part and its whereabouts? 

Pics to come

>Michael


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## TheSchwartz (Sep 3, 2014)

Yesterday was an interesting day. Back on day one when I removed my hot pipe I saw that the connectors on the coils were falling apart and needed replaced. I went ahead and ordered a set of 4 figuring that I would replace them when I was done with the valve cover gasket. Yesterday I set about changing the gasket and when I removed the coils the fun began. First off, the spark plug tubes where full of oil. How much oil? Well, it filled the tube to the gasket, all 4 of em'! 

Good news, I think someone replaced the head. Its very strange though. I will admit the belt was a Contitech but the waterpump and tensioner both appeared stock and their associated bolts had no marks on the edges you would use to loosen them. Could the belt have snapped, trashed the head and someone, or some shop, replaced the head and belt but left the tensioner and pump?

When I finally got to the wiring harness I was pretty upset to find that one of the wires jacket was shot all the way back to under the battery tray. Almost all of the heavier gauge wire in that harness was showing signs of heat damage and had to be replaced. Fortunately all of the smaller gauge stuff was fine and only the one wire was bad enough to trace back down the harness and replace, it was brown (colorblind) I believe it is a constant hot wire. The other really bad wire in the harness is the ground loop, the jacket on it was shot too. Im gonna look into spinning the coils 180 and moving the harness forward on the motor. 

Clean coils, new plugs.

>Michael

one well oiled spark plug









Note the how clean the aluminum of the head is and how dirty the aluminum around the crank is.









Again note the difference in color between the head and the cam hardware, the valve cover was also honey brown inside









The old harness, your service has has come to an end









The offending wire, sorry about the washed out picture, my phone sucks. you can see where I cut it back to in the background









Finally the new harness, I just have to tie the grounds into a loop and tape it off.


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## crazybohunk (May 24, 2011)

Hi there,

You have quite a list to deal with but I will chime in on one of them... well maybe a couple

Once you get to the key replacement you can get the key from the dealer cut and the remote section that goes on top.

But you do not have to have the dealer program it blah blah blah for a fortune.

Because you have the 2001 one version like me the immobilizer bs is not a problem you just need the original key to program the new one.

This is for the functions open door trunk etc.

Even without the programing which you can do yourself the new key will start it and it will stay running from my personal experience.

Now the newer ones have an issue won't stay running but not your vintage.

I also have vagcom and have played around with it a fair bit.

I am also familiar with the Haldex system having autopsied mine and a donor system including a complete rear diff.

I have a number of posts on the crappy cargo pump or pre charge pump on the haldex which is a common problem.

You can ask me questions & I will see if I can help out.

Welcome and good luck


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## PLAYED TT (Oct 17, 2010)

Seems like you got yourself a nice little project! You came to the right place for help (for the most part):wave:


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## whitepatch (Oct 7, 2014)

Mystery mod in the picture, shiny piece: funny that i know what it is because i recently broke it on my 2001 audi tt roadster when replacing ignition coils. simply its a brittle, hard plastic tubing that connects to the vacuum reservoir [side inlet]. to recreate the tubing, i purchased a short length of 5/16 inch OD aluminum tubing and bent it to shape like the broken piece.


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## TheSchwartz (Sep 3, 2014)

Huzzah! The mystery is solved! But seriously, I appreciate it. I hate the look of that aluminum bung, it sticks out like a sore thumb. I had to replace one of those plastic hoses under the intake manifold, it was split from tip to tail. I now can see into the future, and its 5/16 aluminum tubing being painted black! Thanks again!

>Michael


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## TheSchwartz (Sep 3, 2014)

Today I pulled the TT out of the shop, finally, with no check engine light!

The ESP light is on when I start or comes on shortly after I move the car and will not turn off. I checked the wiring to the Haldex and it all looks very good. with the key on engine off I can stand at the rear of the car and hear what I believe is the cargo pump going crazy. Clicking on and off again, seemingly randomly. The ABS unit is still saying there is no communication with the Haldex, although I can connect with the AWD unit with VagCom to read and clear codes. There is a difinite grind, almost a tire dragging, at low speeds when cornering <5mph.

I'm not sure how to proceed with the Haldex unit. I plan on doing some more research but the questions are 

How do I tell if its the cargo pump going bad or the controller?

If the cargo pump is bad and I replace it what are the chances that the controller is close behind?

Would I be better off getting a used rear end?

>Michael


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## crazybohunk (May 24, 2011)

Hi there,

When the cargo pump or pre charge pump fails you have no quattro just front wheel drive.

So based on your problem its not the pump or at least its not contributing to the problem.

So you have controller or rear diff problems.

The clutch plates for the haldex on the diff hardly ever fail so I would look at the controller.

They are available used hell I bought a complete diff with the controller and the pre charge pump for $150 bucks to experiment with.

It looks like you're almost done.


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## TheSchwartz (Sep 3, 2014)

Cool, I kinda figured as much. I guess its time to start looking for a used rear end. Hopefully I can find one local.

>Michael


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## ProjektMK2 (Dec 10, 2003)

Traction control light may be attributed to this. Same issue I'm having.

http://forums.vwvortex.com/showthread.php?4774602-Traction-control-and-ABS-light-issues


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## TheSchwartz (Sep 3, 2014)

Thanks for the heads up, I will read that thread through. Although Im not getting an ABS light, its worth looking into. 

I am headed out for a camping trip over the next few days, when I get back I will get back at the Audi. When I do the list is something like this.

Figure out why the fans still wont work

Finish re-assembling and cleaning the interior. 

Re-install the radio

Find another complete rear end with angle gear and haldex controller, maybe two.

Find out why my door locks wont function correctly

Fix the mix door motor and finish diagnosing the A/C system

>Michael


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## TheSchwartz (Sep 3, 2014)

This morning I jumped in the Audi to go to the store and it gave me a present. 










Note the lack of illuminated service lights! So nice to see!

The fun dont stop there..... soon as I got home I hooked up the VagCom, motor still running) and now it looks like im leaking boost juice (explains the intermitent hesitation) and now there seems to be an issue with the Powertrain Data Bus?!! Grrrr -.- 

>Michael

P.S. Ignore the Airbags and the Door Locks, the buttons for the locks are not installed and neither is the pass airbag light



Sunday,12,October,2014,10:16:17:16235
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 12.12.3.0 (x64)
Data version: 20140905


Mileage: 166270km-103315mi Repair Order: mike-6


Chassis Type: 8N - Audi TT (1999 > 2007)
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Mileage: 166270km/103315miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AMU.lbl
Part No: 8N0 906 018 AT
Component: 1.8L R4/5VT G 0003 
Coding: 06710
Shop #: WSC 00000 
VCID: 830B07EC912AF30606F-515A

2 Faults Found:
17965 - Charge Pressure Control 
P1557 - 35-00 - Positive Deviation
17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!) 
P1297 - 35-00 - 
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 01236 
VCID: 3E7D36183A48DEEEA91-4B18

1 Fault Found:
01324 - Control Module for All Wheel Drive (J492) 
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03 
Coding: 00140
Shop #: WSC 01236 
VCID: 2851F040C8CC705EF3D-2592

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8N8-909-601.lbl
Part No: 8N8 909 601 
Component: Airbag Front+Seite 1008 
Coding: 10102
Shop #: WSC 01236 
VCID: F7F3633CD5F2AFA62A7-5196

1 Fault Found:
01578 - Airbag Deactivation Warning Lamp; Passenger Side (K145) 
31-10 - Open or Short to Ground - Intermittent

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Nx-920-xxx-17.lbl
Part No: 8N1 920 930 E
Component: KOMBI+WEGFAHRS. M73 D08 
Coding: 07244
Shop #: WSC 00000 
VCID: 336B172C010A038656F-4B18

1 Fault Found:
00779 - Outside Air Temp Sensor (G17) 
30-00 - Open or Short to Plus

-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 B
Component: HALDEX LSC ECC 0006 
VCID: 1F43EB9C9D82B7E6827-4B18

1 Fault Found:
01312 - Powertrain Data Bus 
37-10 - Faulty - Intermittent

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels: None
Part No: 8N
Component: Zentralverrieg. D04 
Coding: 00000
Shop #: WSC 00000 
VCID: 860D1EF8A218C62E211-4F1E

2 Faults Found:
01559 - Drivers Door 
61-00 - Won't De-Safe
01560 - Passenger Door 
61-00 - Won't De-Safe

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N8 951 177 
Component: Innenraumueberw. D09 
Coding: 00001
Shop #: WSC 00000 
VCID: FCF97C10ECD48CFE475-5196

No fault code found.

-------------------------------------------------------------------------------
Address 55: Xenon Range Labels: 4B0-907-357-AUT.lbl
Part No: 4B0 907 357 
Component: LEUCHTWEITEREGLER D004 
Coding: 00010
Shop #: WSC 01236 
VCID: E5CF39747F5E2D3688B-51D0

No fault code found.

End ---------------------------------------------------------------------


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## TheSchwartz (Sep 3, 2014)

Got home late Thursday from backpacking in the Sipsey Wilderness, awesome experience, highly recommended. Yesterday was a total wash, sore from tip to tail!

Woke up this morning and headed out in the Audi for a quick cruise. When I first started it there was a howling sound from under the hood, lasted about a minute. The interwebs tells me that it is my SAIP, and the housing is probably separated, add it to the list. 

I need to check the function of the fans still, but Im beginning to suspect that the fan motor may have gone bad and is causing the problems. I have never seen it run on low and have read that it can be a problem on higher mileage cars. I have replaced the controller and it has the green sensor so that only really leaves the fans from my understanding. 

As I was driving along I noticed a clicking/tapping noise while passing parked cars. The noise is related to engine speed and is varying in volume, It is not related to vehicle speed at all. I have heard all kinds of rod/wristpin and valve noises and it dosent sound like any of those. I made a video, you can hear the noise on decel. 

The car will sit until this noise is explained.

>Michael

[video]http://vid376.photobucket.com/albums/oo209/Mosothanu/Audi%20TT/20141018_120334_zpsem5qoqhx.mp4[/video]


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## TheSchwartz (Sep 3, 2014)

Got under it today. The accessory tensioner and cam belt tensioner are functioning normaly. The sound seems like its coming from under the valve cover. Cam chain tensioner. Looking back through my photos its plain to see that its the factory one, its coloring is identical to the cam caps and the valve cover. I will be ordering one tomorrow, along with the chain. 

Any suggestions on why it decided to make noise now? Only thought I had was that I just changed the oil, its possible that someone had put some kind of additive in to help quiet it down, maybe? 

>Michael


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## mochap (Jun 28, 2010)

About the fans, try reseating the 30A fuses(green) on top of the battery box. This may solve you a/c problem as well.


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## TheSchwartz (Sep 3, 2014)

I wanted to get back to this thread because I fixed a bucket of problems over the last few days. Here are my findings

I had a vacuum leak under the manifold still, it was the lines for the FPR and obviously was effecting fueling.

The cam chain tensioner was bad and was knocking, the chain, tensioner and associated gaskets have been replaced.

The A/C pump is making noise, it was contributing to the sounds I was getting from under the hood but was mostly covered by the cam chain tensioner. Really the car sounded like a bag of hammers.

The cheap replacement MAFS is crap and I have ordered a used Bosch unit. The cheap replacement MAFS is supplying bad information to the ECM and that is causing my p1557 and p1297 codes. I am not the first person with this problem, it is a known issue. 

The reason my fans have been acting up so bad is because of the sensor in the radiator. I really chased this problem everywhere. The fix was so simple and cheap.

The issues with the dome lights, map lights, alarm, door locks, and windows were all the fault of the Central Locking Module ( sometimes called the Comfort Control Module and other such terms) If you look at the logs from VCDS you can clearly see that the module has a soft coding of 00000, basically no instructions at all. I believe this may have been intentional as I also believe that the car was fitted with an aftermarket alarm at one point and has sense been removed. After some searching I came up with a factory coding of 15916 and BAM! everything works!

I have also ordered a Haldex fluid and filter kit as I will be addressing my Haldex issues next now that the vehicle is functioning correctly.

I hope this helps someone else, as I thank all those that helped me. 

>Michael


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## hunTTsvegas (Aug 27, 2012)

Great work! Love the determination!


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## TheSchwartz (Sep 3, 2014)

Thanks for the props!

I have never had the experience of owning a vehicle with heated seats. 

I woke up this morning to find that it decided to get cold here in NOLA, 48deg cold, and for us southerners thats down right chilly! So I set about my dailys and before I knew it I was headed out of the house. I slid into what I believe was a seat made out of shaved ice. I kicked on the heaters in the seat and set the heater on HI and in a few moments I felt like I was sitting on the hot rock by the campfire! Great! By the time I had made it out to the coffee shop, about a 5 minute drive, I had to turn the seat heaters off. The actual heater seemed to be struggling to pump out the heat tho, I figured the car wasnt quite warm yet, but by the time I made it to my next stop it was pretty obvious that I have a heater problem. 

It seems to me that whatever is making my heat warm and not hot is probably the same reason that my A/C blows cool and not cold. I do have a code from the HVAC.

Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03 
Coding: 00140
Shop #: WSC 01236 
VCID: 2851F040C8CC705EF3D-2592

1 Fault Found:
00604 - Potentiometer Positioning Motor for Air Flow Flap (G113) 
29-10 - Short to Ground - Intermittent


Now, I thought that the G113 monitored the v71 and was under the impression that these dealt with the outside/recirc flap. Am I wrong there? I do hear a clicking noise from behind the glove box from time to time that I tracked to a servo between the airbox and passenger side of the car that I believe is the servo for the recirc flap. I really doubt that this is a case of bad heater core, when I removed the old coolant to change the water pump it looked super clean, also the thermostat and coolant housings seemed very clean. I was goinna do the old heater core hose test but I cant find a place to grab the hoses thats not stuffed behind the motor. 

>Michael


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## TheSchwartz (Sep 3, 2014)

I received my Haldex fluid kit from ECS the other day and decided to do the service yesterday. After removing the filter I noticed something wasnt quite right. At first I figured I had just ordered the wrong filter but after some research it became clear that the situation was much worse. 










From what I have gathered from the interwebs, this is/was the factory original filter. The oil was black and very thin, but didnt seem grainy/gritty. I finished the service and immediately removed the fill plug from the diff, stuck my pinky in and pulled out thin black fluid. Draining the fluid from the diff had the same results, no chunks and not gritty. The diff did have some shavings on the magnetic drain plug and also carried some metals in the fluid itself, not surprising for its assumed age (103k). I had some Amsoil 75w90 Synth GL-4 Trans fluid, which is what Amsoil suggests, so that is what is in the diff now. After completing the fluid services I checked with the key on/engine off, I can still hear the cargo pump clicking on and off. I will be checking the wiring next, although the connectors look very clean. 

When I was checking for boost leaks I had noticed that the PCV housing was leaking. I received the valve and housing yesterday and figured I might as well get it on so I could finally put my engine covers back on. Then this happened...... and now Im waiting on parts!

>Michael


----------



## TheSchwartz (Sep 3, 2014)

I know its been a while, but Im back! Some quick updates and questions. 

I took the Audi home to Ohio for my Xmas trip and the car ran like a champ! That is it ran like a champ until it got to the OH and the fuel pump shat the bed! So a call to ECS and wala, new pump. That was the one and only time the Audi has left me out in the cold sense its purchase so I am feeling pretty good at this point. 

I changed the Haldex controller with a known good unit with low miles and I am still getting the same issues. I get a clicking from the rear end area and the Cargo pump runs erratically. It is on the list for sure. I need to check for voltage at the Haldex connector as well as the ABS pump. If anyone can explain to me where to check for voltage at the ABS pump, I would greatly appreciate it. 

Now for the issue that has me back. The car is still getting too hot! I have replaced both radiator fans, both coolant pumps, the thermostat, both coolant temperature sensors, the fan controller twice, and the battery fuse panel and connector. The issue is as follows.

Start the car cold in the morning and warm it up by driving like a normal person would
The car warms up to operating temperature, needle stays in the center
Sitting in basic traffic, stop and go, has no effect on the needle
Sitting in a drive through or waiting in a long line to pay a toll the needle rises to the 3/4 mark 
The fans kick on, both of them, at a unknown speed (maybe hi, maybe low have no way to compare as they only come on at one speed)
The fans kick off just before the needle lowers back down to the middle
The needle continues to lower until about a hair above where it should be before beginning to rise again
This cycle will repeat until you get moving again, the car never "overheats" 

I have ran both fans outside the car at both speeds, both the new fans and old fans preformed properly, the old fans were a bit loud and were the original Audi units
Both radiator hoses get quite hot
No loss of coolant 

I have thought about a bad thermostat but this happened before and after changing the thermostat, the thermostat came in the ECS ultimate timing kit.
I have thought about a bad radiator but the coolant was clean when I changed the thermostat the first time
The head was changed a few months before I got the car, it is possible that the PO had the radiator flushed at that time, I have no idea if this happened or not


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## bwdz (Jan 21, 2015)

The coolant sensors are notorious for going bad. Mine is misreading about 20 degrees low right now


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## TheSchwartz (Sep 3, 2014)

both sensors are new. 

are you saying that one is bad? which one do you think it is? 

which sensor of yours is reading low, and what effect is it having? how did you determine that it is reading low?

If this is causing my problem what do you propose i do to fix it?


----------



## asiwa (Dec 18, 2014)

I'm a tad late to this party, but I figured I would contribute what I have 

I suppose I'll address the overheating first, since that is an ongoing and possibly serious issue.

My car had some very similar symptoms from the day I purchased it. Even in the frigid winter weather it would creep up past the center line on the dash and climb all the way up to/slightly over 3/4 on the temp gauge. It was never predictable and would mostly move around arbitrarily and it got very irritating. I replaced the A/C fan (it was seized and not working but inherently not the problem) as well as the coolant temp sensor and even the more reliable radiator fan switch. I did a coolant flush and bleed and still had the exact same problem. 

When I did my timing belt shortly after I bought the car, I neglected to replace the thermostat as there was a more pressing matter I had to attend to at the time. With nothing left to lose I figured I would replace it, even though I knew that it was not typical for a thermostat to be stuck closed/mostly closed. I pulled it out anyway and it was the wrong freaking thermostat! It was rated at 10 degrees higher than the one intended for our cars, and was making the car constantly run hot, but not entirely overheat. I know you said you have already done the thermostat service, but even a simple oversight like a thermostat rated for 190 instead of 180 can cause all kinds of bizarre stuff to take place.

The Haldex business is another area I am well versed in  like quite a few others I have a lengthy documented experience with the exciting Haldex coupling. I only just recently FINALLY rid it of the last issue, but I'll give you what I know.

I don't know what codes you're throwing now, but the powertrain data bus code can indicate a bad pin(s) on either end of the harness that connects the controller to the ECU on the back of the differential. Those pins are infamous for corroding and causing resistance which can potentially damage the controller or simply cause improper operation, even if you have a confirmed working controller. It's more common for the male pins on the controller plug to go bad but the female end attached to the car can be affected as well. The only way to rememdy that would be to buy a new plastic plug and splice the wires in.

It is a tad...troubling honestly...that your car had the stock metal filter still on the car. The Haldex fluid is very thin by nature so unless you had another serious symptom like excessive bits of metal in the fluid it's frankly not as big a deal as it's made out to be. I've heard that the dealers frequently omitted the filter part of the service on these cars just because I guess. As long as it's changed now you should be in good shape. 

A word of note on the pump - I've seen varying accounts but in accordance with the factory training manual the pump should only run when engine RPMs are above 400 - that is not at all unless the motor is running, or unless you specifically initiated the Haldex output test through VCDS. If you're just turning the key to accessory you probably shouldn't hear the pump at all, but again that's something I've heard different stories on. 

Something I could recommend is opening the AWD module on VCDS, and once the controller information loads go into "Measuring Blocks". In the top row clicking up to Block 001 yields brake switch information and Block 002 yields controller voltage and fluid temperature info. Make sure you do this with the motor running to be sure the controller is being supplied ample voltage. I believe the normal range is between 11V and 15V, but I'll check tomorrow to be sure. If voltage is excessively lower than that you could have bad pins. This could cause the motor inside the controller (the one that regulates the oil pressure on the clutches) to operate improperly. Let's see the results on that test and we'll go from there. 

I know that's an annoyingly long paragraph of info but all of this is what helped me solve the issue on my car. Good luck man!


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## TheSchwartz (Sep 3, 2014)

I love annoyingly long posts, and to prove this here is one of my own!

Lets start by saying that when I bought the car the very last thing the salesman told me before driving the car off the lot was "Leave the AC on or the car will overheat! Enjoy your new ride!" What a D-B. 

Lets follow that with some facts about the Audi TTQ 225

Thermostat opening temp - 87 (all numbers will be in deg Celsius)

on/off
Low cooling fan temp - 95/84
High cooling fan temp - 102/91


Now I started off this morning with a cold car and an ambient temprature of 77(degrees Fahrenheit), started and set the Climate Control to 49C (engine coolant temprature) with a reading of 30deg Celsius. I took the car out for a few blocks to get the temprature starting to rise and finally got onto the freeway with a temp showing 75 on the CC.

After a spirited run on the freeway that took about 15min the CC was showing the engine coolant temp was hovering at about 93. Still too cold to get the fans to kick on but this is operating temp for the motor, the needle on the dash is standing straight up and I believe this is normal. The thermostat opens at 87, coolant temperature of 93 = 5 degrees variance, well within variance for any sensor or thermostat.

I arrived at my local drive through coffee shop with a coolant temperature of 93 degrees and while waiting on my Venti, tripple, non-fat, halfcaf, blended, with whip, hippie mocha (not really) I watched my coolant needle climb. At its very highest point on the needle the coolant temperature just kissed 102 on the CC. If this were at the radiator it would just barely be enough to trip the high fans, but its not!

The coolant temperature is taken just beside the block, the fan switch is located in the side of the radiator. These two might as well be a mile away from each other! With a coolant temprature of 102 at the block I am only reading about 96 in the radiator, just enough to trip the low fans! You see the issue here isnt that the TT is overheating, quite the contrary, the TT is running COOL!! The combination of a large radiator and movement are enough to keep the motor plenty cool most days without the use of the coolant fans. My big hook was seeing the needle move before the fans came on, which was a red flag in my book. Truth is that the space between the needle standing straight up and the needle moving one tick right was only a variance of about 7deg, no where near enough heat to bother the engine and just enough heat to trip the fans on low. Just to make doubly sure I pulled out my infared thermostat and checked the upper and lower radiator hoses and low, what did I find? Perfection! Neither the hoses or the radiator were of a temperature that was bothersome to me, also if you watched the temperatures you could clearly see the thermostat opening and closing, even though the change was only a few degrees, it was there and thats good by me!

So, the TT is running just as it should, for now. On to fixing the AC, its getting hot out there!!


----------



## whitepatch (Oct 7, 2014)

*thank you for your posts*

hi michael, 

just so you know i appreciate your postings, thank you. i'll be working on my 2001 Audi TT Roadster 225 soon, once it gets warmer here in NJ.

i also had a problem with my heated seat. on mine, the driver's side bottom pad will not heat up, but both bottem side bolster and back would, really hot, even if i set the dial to low. as i found out via Googling and the Audi Service Repair Manual [ElsaWin], there's a seat temperature sensor built into the system and i figured there's a broken heating element. so, after watching a Youtube video of an Acura owner fixing his broken heated seat, i got the nerve to take out the TT driver's seat, remove the bottom pad from the seat unit [easy to remove, kudos to Audi for the design] and separate the leather from the foam pad [remove the hog rings]. with the use of a multimeter, i systematically tested the wire heating elements section-by-section by exposing portions of the wire; i used a cutting blade as the wires are glued onto the foam pad and the covering cloth that was deteriorating. lo and behold i found the break in the wire. i soldered the connection and covered with electrical tape all the areas where i exposed the wires. before putting everything back, i tested the seat bottom. voila! my heated driver's seat is working again.

thanks again.

jess


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## TheSchwartz (Sep 3, 2014)

Congratz on fixing your seat heater. Nothing like it when its frigid outside! 

And now back to the Haldex!!

So I have tried replacing the controller, with no positive results. 
I can connect to the controller through the VAG COM cable but I have had trouble at times reading the codes out of it. The controller seems to respond to the VAG COM because as soon as I log into the controller it stops making noise of any kind. 

I can also log into the ABS controller with no issue to speak of. It will also preform all of the basic tests without flaw, so Im pretty sure that there is a problem with the wiring that goes from the ABS unit to the Haldex controller and I believe its most likely between the Haldex controller and the ECU as well because sometimes the Haldex will report problems contacting the ECU as well as the ABS and will even flag the DATABUS as faulty. 

So the question is, after the Haldex controller plug where does the can bus wiring go? where is the next place that I will be able to test the can bus wiring for continuity?


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## bwdz (Jan 21, 2015)

Forgot to check in on this. I say my sensor is reading off because I checked it with several different infrared thermometers. My gauge stays just below the halfway mark 90% of the time. Like your car, when sitting in traffic for a while it rises past the half mark and fans kick in and then temp comes back down. I was concerned so I started checking around with infrared sensor (cheapie from Harbor Freight but works spot on as I used frien's Snap on one and we get same readings within a degree) I was comparing the temp with what we were getting right by the rad sensor.


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## TheSchwartz (Sep 3, 2014)

So...... 

My Haldex started working?!....... sometimes!

I think I may have an idea why.

More to come.


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## chabon (May 5, 2015)

TheSchwartz said:


> So......
> 
> My Haldex started working?!....... sometimes!
> 
> ...


and the answer is???? This is like reading a novel with the last page torn out!!!


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## TheSchwartz (Sep 3, 2014)

Thats a fine question. 

Either the Haldex control unit or the ABS unit has gone, Im leaning to the Haldex unit. Either way whatever has been causing my issue is temperature sensitive. 

The system functions normally if the ambient temperature is between 70 and 75, you warm it up with a jog down the freeway, and finally you must turn off and restart the car. 

I would guess its the Haldex controller because of the following
1) The Haldex unit will click over and over again regardless of weather the pump is plugged in or not
2) The ABS unit is accessible in VCDS and will preform all tests and report all sensors without issue or fail
3) the Haldex unit will only report in VCDS from time to time and testing can return various results
4) the cargo pump will cycle with VCDS
5) when the Haldex does decide to work it works flawlessly, just as intended. I would not expect this to be the case if it were a wiring problem. It would likely not ever function properly

At this point I only have two choices:
1) Take the car to Audi and see if they can give me a more definitive answer (I am unsure if they can tell me more than i already know)
2) Replace the Haldex unit again and hope for better results

I am unsure where I want to spend my 200-300 bucks.

On a positive note, I fixed my A/C last night. Soooo Nice!!


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## Volksdude27 (Nov 25, 2005)

Had the same problem when I first got my TT. After coutless hours reasearching what could cause that I found out that many people never did oil service in their haldex units leading to these failures ( damn even some dealers didn't had a clue what I was saying about haldex oil services... ) 

If you're lucky an oil service on the unit might solve the problem. If you're like me, a unit change ( even for a used one that has been maintained properly ) will solve that problem for good. Don't forget to do the oil service on the recommended interval afterwards tough.

If you ever need a unit you can swnd me a PM. Just upgraded for a blue controller so my oem unit ( that was factory refurbished when I installed it in 2011 ) can be up for grabs


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## TheSchwartz (Sep 3, 2014)

I know how you feel about those Haldex fluid changes. When I received my TTq I decided to swap out all the fluids just to bring the services up to date. When I attacked the Haldex I was shocked to find that it was sporting the factory original metal filter!! It had clocked over 100k on the original oil. 

I plan on changing the fluid out again in the next few weeks, after that I will be attacking the AWD system again with an intention to finish this bad boy up.


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## TheSchwartz (Sep 3, 2014)

Just a couple quick updates here. 

First and foremost, I no longer believe that my haldex controller is bad. After extensive testing on the controller and wiring I have determined that they are both in perfectly serviceable condition. I also spent some time looking at and researching the ABS unit. Apparently the Bosch ABS units that the TT comes equipped with are known for failing. Not surprisingly when they fail they often throw codes for memory issues, pump issues, and communication issues, mine is chucking comm codes. The final straw that made me change my mind came while I was waiting on a coffee at a local drive through coffee shop. While sitting with the car aside the building, listening to the car idle, I noticed that the haldex was no longer "clicking". When I depressed the brake pedal I could hear the infamous "click", just once, again I let go of the brakes, no "clicking", depressed the pedal once more and "click". I have determined that the clicking is the solenoid inside the haldex controller. Unlike the brake light, the brake signal is sent to the Haldex from the ABS unit along the Comm lines. If I was forced to guess I would say that the brake light signal is a redundancy built in just in case the ABS unit fails to send the brake signal to the Haldex. None the less, my current belief is that the ABS unit has a faulty pin connection internally and that is causing it to send inconsistent brake signals to the Haldex, sometimes the connection is forced together when the temperature is just right causing the system to function properly for a time, not unlike wiggling a poor power connector in its socket to make your laptop charge one last time. Remedy = change the ABS. This is something I plan on doing over the next few months, time and money permitting. 

In the mean time.....

The check engine light came on the other day! A quick scan with VCDS shows that the MAFS is not reporting. I have cleaned the connector and the sensor with no positive results, and so it must be replaced. If you took the time to read this whole thread you will know that I have been down this road before, once with a cheap china MAFS that only worked to hack apart for a boost leak detector and otherwise be avoided at all costs. So I currently have a JY bosch MAFS and im looking to replace it with another, 150 for a new one is just too rich for my blood. So now I get to the root cause of this post, the MAFS. Currently my car is equipped with a 06A906461EX, from what i gather the car was originally equipped with a 06A906461E. Now we all know that you can get the sensor out of the housing by removing the security head torx, my question is what other cars use that sensor in a different MAFS tube? I know that the sensor is a Bosch F 00C 2G2 040 and after some research I have found that that sensor is in the MAFS of some 180 TTs as well as some Golf IVs. Anyone have any ideas where else I might locate that sensor?

Update
I found a sensor yesterday. swapped it out and now the check engine light has gone out, so all good. The sensor came out of a 00 Jetta 1.8t with a mafs part number 06A 906 461 D.

just to recap

Mafs Sensor PN
F 00C 2G2 040

Source Mafs
06A 906 461 E
06A 906 461 EX
06A 906 461 D


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