Need some advice on Air conditioning diagnosis - Not blowing cold

Oskar

Oskar

A2OC Donor
Hi all
I have read a large number of posts on this excellent site, but cannot get to the nub of my problem. AUA petrol 2001.

Air con worked extremely well last summer. It has stopped being cold sometime over the last few months.

Current Situation
1- System is gassed and pressurised. Was fully serviced under a year ago, and is still under good pressure
2- I have no errors on VCDS lite (registered), and have never had any under HVAC or A/C related (except connection below).
3- I have not previously changed any sensors. The current compressor has unknown history, but has worked well since the A/C service
4- After some dash work, I have experienced intermittent connection errors between the HVAC controller and the instruments, engine and comfort (photos attached), however once the HVAC unit connectors are reseated, and the errors are cleared, all is well. I am reasonably sure these are just connector issues on the back of the HVAC controller (but happy to be informed otherwise). I have not had these errors for a while, and the non-cold remains.....
5- Radiator fan runs at all times. Replacement fan module installed (just because I had one) but no difference (as expected).
6- Radiator fan turns off when unit is in ECON mode. Interior fan changes tone markedly when ECON is on.
7- There is no 'weak cold' at start-up, or any sign of A/C working at all.
8- Using VCDS, all the Output tests appear to work as expected (flaps, heating etc)
9- I cannot access the hidden menu (Top and recirc buttons), but it appears this is normal for an A2.
10- First 18 measuring blocks are attached. Group 2 indicates compressor is ON (this shows 6 when ECON is pushed. When ECON is turned off, it flashes to 12 for less than a second, then back to 0).

Am I looking at a dodgy sensor, even though no codes suggest this, and if so, which one, or perhaps a N280 on the compressor?????

The answer may be in front of me, but I cannot see it, so hope one of you experienced folk and point me in the right direction.

Thanks

Matt
 

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@Teresa had the same problem, and comms to AC error message recently, and it wouldn't reset. I ran a auto scan, on my OBD Eleven, then ran clear all faults, as all controllers, and comms was restored and AC worked. Seems some controllers get their underwear in an uproar, lock up, and don't respond to the VCDS reset. I have no explanation, but it did work.
There are vag eprom reading utilities, that include clear DTCs, so that's worth a try.
Mac.
 
Good Evening Matt,

I know little about the A/C system and cannot help but just a thought.

I looked at your measuring block screens and what struck me was I had no idea what I was looking at, the reason beside my own complete ignorance is that no label file is active. As a consequence VCDS is displaying block generic text and no group descriptions, not a very helpful situation. From your previous experience/research you may be already familiar with these blocks but if you need further help as a registered VCDS user you could ask Ross-Tech if they can help with a label file, after all you have paid for assistance. A quick glance at Youtube does show HVAC label files are out there, albeit for slightly later other non A2 models.

If you email RT do enclose an AutoScan, they can only say nothing available in English but other languages might be and that is no problem there these days.

Andy
 
There have been similar issues with Mk1 TT HVAC label files.
At least one member has created a DIY HVAC label file, using a label file from another model, (A3), of similar vintagewith the same Climatronic system, as a basis.
The A2 Climatronic is the same as the A4, I think.
So, an edited version of the A4 HVAC label file may provide a work around, particularly for us Lite users.
Mac.
 
I can make you a label file if you wish? All of the information needed is in the service literature
 
PlasticMac said:
There have been similar issues with Mk1 TT HVAC label files.
At least one member has created a DIY HVAC label file, using a label file from another model, (A3), of similar vintagewith the same Climatronic system, as a basis.
The A2 Climatronic is the same as the A4, I think.
So, an edited version of the A4 HVAC label file may provide a work around, particularly for us Lite users.
Mac.
Click to expand...
The scan report I got from OBD Eleven, on the @Teresa A2 looks like this:

08 Air Conditioning
System description:
A2-KLIMAVOLLAUTOMAT 0510
Software number: 8Z0820043G

I've queried it with Ross-Tech, and they say that controller is supported on the current release of Full VCDS. So, could anyone with Full VCDS please check?
Sadly, it's not supported on Lite, and won't be.
Mac.
 
a-zwo said:
Yes that was just for the engine. There needs to be a label file for each module.

I will try and make this for you today :)
Click to expand...
I won’t be back with the car until the weekend, so no hurry. Thanks again.
 
a-zwo said:
Yes that was just for the engine. There needs to be a label file for each module.

I will try and make this for you today :)
Click to expand...
According to Ross-Tech, if you have full VCDS, (which I think @Oskar has) the HVAC label file is already available. If it's not present in the label folder, download the latest update.
Mac.
 
PlasticMac said:
The scan report I got from OBD Eleven, on the @Teresa A2 looks like this:

08 Air Conditioning
System description:
A2-KLIMAVOLLAUTOMAT 0510
Software number: 8Z0820043G

I've queried it with Ross-Tech, and they say that controller is supported on the current release of Full VCDS. So, could anyone with Full VCDS please check?
Sadly, it's not supported on Lite, and won't be.
Mac.
Click to expand...
My module has that code, but without the G on the end.
 
PlasticMac said:
According to Ross-Tech, if you have full VCDS, (which I think @Oskar has) the HVAC label file is already available. If it's not present in the label folder, download the latest update.
Mac.
Click to expand...
I only have Lite alas. It looks like the measuring blocks are the same format/layout, but just without the labels, but only a full VCDS comparison with the 18 groups I have posted will confirm that.
 
Oskar said:
I only have Lite alas. It looks like the measuring blocks are the same format/layout, but just without the labels, but only a full VCDS comparison with the 18 groups I have posted will confirm that.
Click to expand...
I'm a Registered Lite user too. A Lite version of the HVAC label file would be useful.
I also use OBD Eleven, and the basic VAG only, dongle, for Android is only £34.99, app is free. Bluetooth, so no wires. Worth considering, certainly.
The ability to email all reports direct to yourself is very convenient too.
Mac.
 
Oskar said:
My module has that code, but without the G on the end.
Click to expand...
The G is, I suspect the software issue, which came via the OBD Eleven scan.
I didn't save the pre clear scan I did for @Teresa but from memory, there were the same no comms from HVAC to ECU and Instrument Cluster.
I'd certainly try the vag eprom programmer v1. 19 utility, which has a clear fault codes function. Once the HVAC Controller is reset, comms to ECU and Instrument Cluster will be restored, 🤞
I've used it for other functions, and it works. Same cable as Lite.
Mac.
Edit: "Please ignore the stuff about VAG EEPROM, as I don't think it'll communicate with the HVAC Controller. .
Mac.
 
Last edited:
Good Afternoon,

First apologies to Matt that my post has caused a great thread swerve.

I looked in my full VCDS Label folder and like Matt I have 8Z0820043.lbl (no G). Looking inside this file with Notepad the groups at first glance appear well documented but in German, for example a machine translation of Group 1 by Deepl gives

001,0,General
001,1,Compressor,control valve (N280),value range: 0.0...1.0 A\nSetpoint: 0.3...0.8 A
001,2,Compressor,control valve (N280),value range: 0.0...100.0 %\nSetpoint: 30.0/40.0...100.0 %
001,3,High pressure sensor,(G65) duty cycle,value range: 0.0...100.0 %\nsetpoint: 12.0...87.5 %
001,4,High pressure sensor,(G65) Pressure,value range: 0.0...40.0 bar\nsetpoint: 2.6...29.0 bar

It helps if you are familiar with label file syntax!

Why Matt does not see the file used I can only guess - some sort of language parameter at VCDS Lite setup set to English???

However I have just tried with my full VCDS and the label file is active.

1713196729222.png


I think the next step is for Matt to ask RT why the label file is not loaded when he has it.

Andy
 
Last edited:
Andrew said:
Good Afternoon,

First apologies to Matt that my post has caused a great thread swerve.

I looked in my full VCDS Label folder and like Matt I have 8Z0820043.lbl (no G). Looking inside this file with Notepad the groups at first glance appear well documented but in German, for example a machine translation of Group 1 by Deepl gives

001,0,General
001,1,Compressor,control valve (N280),value range: 0.0...1.0 A\nSetpoint: 0.3...0.8 A
001,2,Compressor,control valve (N280),value range: 0.0...100.0 %\nSetpoint: 30.0/40.0...100.0 %
001,3,High pressure sensor,(G65) duty cycle,value range: 0.0...100.0 %\nsetpoint: 12.0...87.5 %
001,4,High pressure sensor,(G65) Pressure,value range: 0.0...40.0 bar\nsetpoint: 2.6...29.0 bar

It helps if you are familiar with label file syntax!

Why Matt does not see the file used I can only guess - some sort of language parameter at VCDS Lite setup set to English???

However I have just tried with my full VCDS and the label file is active.

View attachment 122510

I think the next step is for Matt to ask RT why the label file is not loaded when he has it.

Andy
Click to expand...
Hi Andy
I have very few label files, and certainly don’t have that one. Could you please PM it to me? I downloaded my lite from Ross Tech and am registered, but perhaps there are many label files that don’t come (automatically) with lite?

Then I can see if something looks odd….

Thanks

Matt
 
Back to your original issue:

I would guess the compressor has seized. The AC unit is supplying current to N280 to turn on then compressor, and you have 6.4 bar of base pressure which is enough, but there is no cooling.
 
Someone will correct me, but to check that, you can either start the engine and see if the central part of the compressor pulley is turning.
Or, with engine off, try and turn the central part of the pulley.

If you can turn the central part by hand, or it doesn’t turn when the engine is running, then a new compressor is in order.
 
Oskar said:
Hi Andy
I have very few label files, and certainly don’t have that one. Could you please PM it to me? I downloaded my lite from Ross Tech and am registered, but perhaps there are many label files that don’t come (automatically) with lite?

Then I can see if something looks odd….

Thanks

Matt
Click to expand...
Good Evening Matt,

I have an idea why you do not have this label file; looking at the file it was written in the Spring of 2013 while update support for Lite ended in 2012 - it missed the boat.

I have attached the label file for you and any other Lite users, I expect/hope it will work fine but if not running the entire file through a machine translator will give a very good idea about each group and its blocks.

Important Note.

Due to a restriction on the forum upload permissible file types I have had to change the file type to .txt, it needs to be changed back to .lbl for use in the VCDS Labels folder. You will get a Windows warning about changing file types, ignore it and click Yes.

Helpful Hint.

Before changing the file type check that Windows is displaying file types, otherwise you might think you have changed it to .. .lbl but it is actually .... .lbl.txt and VCDS ignores it. There is system setting somewhere dependent on Windows version - it should be set to 'Show file extensions'.

Andy
 

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Last edited:
PlasticMac said:
The G is, I suspect the software issue, which came via the OBD Eleven scan.
I didn't save the pre clear scan I did for @Teresa but from memory, there were the same no comms from HVAC to ECU and Instrument Cluster.
I'd certainly try the vag eprom programmer v1. 19 utility, which has a clear fault codes function. Once the HVAC Controller is reset, comms to ECU and Instrument Cluster will be restored, 🤞
I've used it for other functions, and it works. Same cable as Lite.
Mac.
Edit: "Please ignore the stuff about VAG EEPROM, as it's only communicates with ECU.
Mac.
Click to expand...
Use the lbl file @Andrew has posted, to clear the HVAC fault codes, and see where you are then. Good luck.
Mac.
 
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