2004 A3 2.0TDI - aircon problems

[MHAD]

Hi. I have an intermittent problem with the aircon in my A3 2.0TDI.

From time to time, mostly on a hot day, the Econ mode foreces to stay on. The Auto and De-Mist buttons when pressed don't turn off Econ mode like they usually would. Pressing the Econ button, it goes out when depressed, but comes on again when released - nothing I do can change this.

Does anyone know what the problem could be?

Thanks!

[Audi Eire]

Hi Mhad, I've seen this before. It was caused by the gas pressure in the system being low. When econ mode comes on this turns off the compressor. When the system is low on gas it defaults to econ mode. One quick way of checking the gas in the system is with the car started and air con on (if climate control set temp to lo) then check the pipes on the compressor unit. The return pipe should be very cold and have condensation clearly visible. This will only give you an indication. Best way to be sure is to get a refrig. engineer to put a set of refrigertaion gauges on the car. It only takes a few minutes and will give an accurate indication of the refrigeration system. The two valve points he needs to go on to are behind the drivers side headlight and relatively easy to get on to. The reason it is worse on a warmer day is that the percentage of cooler air being required to achieve the requested temp in the car is higher thus the compressor has to work harder. Hope this helps. Now if only I could fix my own!!

[MHAD]

Hi, Thanks for the reply. All sounds very logical. I wonder if a diagnostic would pick this up...

I'll post back here on how I get on.

[Audi Eire]

Hi, Diagnostics should show some error as the system is switching to Econ mode itself. Diagnostics will not show low gas though and this is not covered under warranty either!!!

[daniel graham]

Have had the very same problem on mine, have had to have the A/C regassed in the end as it was low on pressure. The gas never seems to last very long, the dealer said it needs doing about every 18 months to 2 years. Would avoid the dealer prices tho as they charged £110 to regas the system and it can be done at most places now for a lot less.