10speed

Does anyone know if a bad ambient air temp sensor could cause AC system shutdown?

lyleswk

That's usually a sign of low Freon.

uberwgn

^^Yes.

Witt_4rings

So low free - on would cause the ECON button to stay on? I have this problem as well.

lyleswk

Yes. It is a self protect feature to prevent the compressor from running out of the lubricant which is mixed with the Freon. Have a reputable A/C shop check the high and low side pressures.

Witt_4rings

I added freon myself but now when I turn car off it sounds like a jet engine powering down just not as loud obviously. Do you think I overcharged it? Or is this normal? Says 510 grams holding capacity I put about 2-300 get in.

lyleswk

No way of really telling without putting pressure gages on it.

Witt_4rings

Most def thanks.

adamhschmidt

@Witt_4rings, my car is having the same issue right now preventing me from passing smog. The ECON light stays on, my engine is super loud and when I turn it off, it sounds like a jet is shutting down (like you said, not as loud though). Did you end up figuring out the problem? it seems like our problems are/were pretty similar, any help would be greatly appreciated.

JJm64123

do these audis have to be filled with a certain freon and oil lubricant? I can't just charge the system with regular freon i can get from an auto parts store? Previous owner disconnected lines after a front end accident and never recharged everything.