Air conditioning help

[Benish7]

Hi, I have a 2012 A6 Avant and recently the AC stopped working. I took it to ATS Euromaster today for a regas and the tech found that the machine removed 560g of coolant from the system before replacing it with 570g (full), but it didn’t fix the issue. So it seems like I definitely had no leaks and only 10g depletion of gas over 7 years.

Strangley enough the AC light will now not stay on unless the AC button is pressed. Before my trip to ATS this light was on permanently, unless switched off.

Can anyone offer any help before I take it for a diagnostic test? This heat wave is a killer with no AC!
(Would a diagnostic test need carrying out at an Audi dealer or can any garage do that for me?)

Thanks

Ben Thomson

Audi A6 Avant 2012 (12) S Line 2.0 TDI Automatic

[Johnny31]

To start with, a scan with VCDS/OBD11/Carista would be very useful and can be done by anyone... Suggest you find a fellow Audi enthusiast to help you. There should be a map somewhere on the forum with all the "willing" people plus you could (I highly recommend) invest into OBD11 or Carista (depending on if you are Android or Apple oriented).

Sent from my mobile...

[Alan02]

The A6 C6/C7 has a common problem with the pressure/temp. sensor failing.... I had this on both models. But a scan for faults would be first step.

[Benish7]

Thanks for the responses.

So I bought the Carista scanner from amazon and ran a scan.
quite a few faults with various things came up but the main ones relating I think we’re
Heater & air conditioning:
00292 - Hydraulic Energy Supply Pressure Level
(If this is AC gas pressure it’s odd because ATS said it was full)
Central electronics:
00256 - Givers for refrigerant pressure / temperature (G395)

Having done a bit of research, the G395 error suggests the LP sensor at the front so I ordered this from amazon
HELLA 6ZL 351 028-361 Pressure Switch, air conditioning HELLA 6ZL 351 028-361 Pressure Switch, air conditioning: Amazon.co.uk: Car & Motorbike (I didn’t want to buy an expensive part direct grommets Audi in case it wasn’t the fault!)

I fit the part this morning. Nice easy job, but it hasn’t worked. The AC button still wouldn’t come on. I thought maybe I’ve fit it wrong so removed it and put it back on again. Only this time the pressure started to leak out. And it came out that fast I couldn’t get it back on in time! (O ring split so had to find a new one whilst it was leaking).
I eventually got it on and ran the Carista scan again. I reset the faults, and then scanned. The G395 issue had now gone.
Should I have reset faults once I replaced the part, to tell it it was fixed?!

Now I’m still getting this error
00292 - Hydraulic Energy Supply Pressure Level

Is this low air con pressure because it’s leaked?

I’m still wondering why the AC button worked and lit up before I went to ATS. After they emptied and re gassed it, the light only comes on on pressing of the switch. I may have to return to ask them.

Stumped.
Any ideas?