svennorske

2006 Audi A4 Avant 2.0T Quattro

1. ECON button starts to intermittently turn on (effectively turning AC on/off). Eventually gets stuck on.
2. Code 00819 indicates Pressure Switch. Shop replaces switch and charges system.
3. Next day ECON is back to flashing on/off. Shop then replaces switch, still no fix. Had replace switch a second time just to be sure, still no fix.
4. The shop was able to observe the system pressure spiking when the ECON button comes on. He thought it could be the computer, but I'm not sure if he meant the actual ECU or something else? I'm not sure what controls this.
5. So changed out Climate Control Unit in-car to a known working unit, still no fix.

Loads of money spent 'diagnosing' with no fix. Could it simply be the compressor? Is there a way to actually test the compressor? I'm at my wits end...

Kchoul

Had exactly the same problem (points 1-4), however, refused to have the climate control unit changed even though it was suggested by the shop, and even a specialized a/c repair shop recommended it as the most probable cause. I insisted on cleaning the a/c refrigerant circuit first which they didn't want to do initially due to the low mileage, approx. 80k miles. My gut was telling me the circuit could somehow be clogging, causing the pressure spikes and damaging the pressure switch. And to everyone's surprise the cleaning worked perfectly, no problem with a/c since then. Both the a/c control unit and the compressor are OK.