Air con problem, completely flummoxed

Hi Folks, I am really hoping someone can point me in the right direction here. I have seached so much in forums here and else where and not found the issue I am having.

History , car sat on the drive with no use during lockdown. Batttery went flat. Recharged . THEN :

1. After starting the fan speed didn't respond on LO and just ran slowly .
2. Ran VCDS Autoscan, only errors related to flat battery nothing else
3. VCDS HVAC no fault codes so in HVAC ran Basic settings as suggested by hits on web.
4. OK now fan run as expected but NO Cold air .
5. All flaps operate as expected
6. ECON light works as expected (not on solid etc)

• This is where I am stuck. VCDS shows no errors
• I am attaching Measurement Blocks for HVAC in case someone can see any issues. From my view it appears G65 OK and Gas pressure I have seen between 6-9 bars. So I don't think it needs re-gassing (re-gassed last year).
• Not sure how to check if the compressor is actually kicking in , but blocks seems to say its working.
• HELP ....... PLEASE

See Blocks below (Hope 18 are enough)

https://www.vwaudiforum.co.uk/forum/i...AASUVORK5CYII=
Attachment 37209
Attachment 37210
Attachment 37211
Attachment 37212
Attachment 37213
Attachment 37214

Sounds a bit like my (solved) issue - if you haven't already fixed, it try the later steps in Solved 2007 TDI Avant - A/c fault - compressor shear link

Hi Plug it in,

Did you fix this?

I have a similar problem and trackguy is spot on (well done you for finding it) the compressor is a vario drive type, mine is a Denso, and is controlled by a solenoid valve (N280) which is controlled via the computerma bob.

Do you know anyone that has ac guages? If so if you hook them up and watch the high and low pressures (Red and Blue respectively) it can tell you a lot.
With the AC off the static pressure will be the same between the two.
Switch the AC on and the Low side should drop and the High side should rise. If this happens it means your comp is kicking in and most likely not the cause.
Ideally you want about 30-40 psi on the low and 150-200 on the high side (this is ambient temp sensitive so will be lower during the winter...your static will read the ambient temp in degrees F)


If the shaft is spinning with the pulley you don't have trackguy's problem and it is likely one of two issues.
1. the solenoid control valve is faulty (even though you are showing a good set of readings from the N280 measure block)
2. the vario swash plate mechanism in the comp is stuck/seized in the off position.

I hope you don't mind but if anyone can help with my story of woe it would be greatly appreciated.

Hello and thank you in advance for taking the time to read this.

I will try and get as much detail down to give the diagnostic heroes amongst you all the info I can.

I am working on my friends 2011 Exeo Sport Tech st. (Audi A4 B7) The AC hasn't been working for a while as it has the dreaded G65 error code/Econ light issue.
So while locked down I offered to fix it!


I replaced the high pressure sensor while it was jacked up on stands having new discs and pads.
I have VCDS and the scan is now clear (apart from glow plug 3!!) and the Econ light goes out but still no air.
The comp is a denso variable model 6seu14c, not the clutch type.
There is voltage at the N280 control solenoid and in VCDS the measure blocks show it operating fine (amps rising and falling when econ button cycled) as is the G65 and compressor state.

With the ac gauges connected the static pressure today was about 50-60 psi which at 14 degrees C seems about right.

The issue is when the air con/Climate button is pressed there is absolutely no movement between the pressures of the high and low side.
As all the VCDS and voltage checks seemed ok I am veering to the variable swash plate in the compressor or the pulley being sheered

Today the compressor came off (after pumping down) and the n280 was tested and the solenoid operates. The pulley was removed and is fine the shaft turns smoothly with no hint of any black death or metal in the oil.

While the comp was off the lines were blown through to check for blockages, none found all pipes seemed clear. The evaporator expansion valve was removed and cleaned/checked, all ok.

With shaft, pulley and solenoid ok the comp was put back on, system vacuumed out pressure tested and re-gassed.

Exactly the same, no movement whatsoever between the high and low gauges when ac turned on.

Has anyone come across this before as i'm scratching my head now?
Does anyone have any wiring diagrams by any chance?

Any help/suggestions as to how I should proceed would be greatly appreciated.

Many thanks,

Mike.