OK guys so a few months back I had an issue with the the EML light and cooling fans and electric water pump. So thr electric water pump had a broken wire which was an easy fix but the cooling fans someone had unplugged so they were replaced but the fans where constantly running. So I saw a post on hear with somebody with the same issue. When we first scanned thr car their was a fault code for the high pressure refrigeration sensor. But when we cleared the codes it disappeared. So I asked the auto sparks to change to see what happens and hey presto it fixed the issue to add to it they had another A6 Avant thr same year ad mine in with the same issues and they were scratching their heads as they weren't sure what the issue was and it ended up it was the same sensor. So fast forward to the good weather and thr fact the wife had been driving the car I forgot about the A/C. So when I select the A/C the light comes on momentarily and then goes off and it won't come back on again. So does that mean I need to recharge my A/C or do I have another issue?

If you need more gas it will go to Econ mode. My advice is to get it pressure tested.