Q4 A/C Malfunction

Amped said:

Had to send our car back to service. AC still wasn’t blowing cold air. 4th times a charm?

Text from our service advisor -

“So we got the system adjusted again and the vent temp is blowing out at 38(f). We think there may have been an issue with our machine we are using. It's a new one but we think maybe the calibration was off on it or something. Cause the past couple times when we did the evac on the system it was saying that it pulled out even more than what the system holds. If the system gets too much in it then that can cause it to not function properly. We would like to do a couple short test drives on it if you are ok with that. We just want to make sure it's not leaking out while driving or something.”

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I bought a Q4 AWD back in Oct. 2022, and I experienced the same problem with AC right away. It was not blowing cold air. And warning messages popped up on the console saying that AC system malfunctioned, and also electrical system had problem. I took it back to an Audi dealer. They had the car for around 2 weeks. First they found that refrigerant was low and they thought there was a leak. Eventually, they decided that the AC compressor was faulty. So, they replaced the AC compressor. That fixed the AC problem and it's now blowing cold air.

However, I found another issue with the ventilation control (I posted this issue on another thread). If I turn on turn on the AC ventilation in a certain sequence, the fan control would not work in the manual mode. I took my car back to the dealer and they spent 5 days replacing a connector switch. But, the ventilation control problem remains. I just took the car to the same dealer and they are still working on it.

took delivery of my 2023 Q4 in late March and with just over 5k kms the air conditioning system is not working. when brand new it was fine in fact too cold at 20c. Now we have aprrox 30c OAT the system is blowing what seems like ambient air (hot)..........going into dealer but theyre backed up, have to wait couple of weeks.

2023 Q4 3K Miles, purchased back in December. AC stopped working today. Dealer in Austin, TX is asking to leave the car for 4 weeks and is not giving a loaner. This is turning out to be the worst decision I have ever made. I plan to trade it in once the AC is fixed. Never buying an Audi again.

Max said:

2023 Q4 3K Miles, purchased back in December. AC stopped working today. Dealer in Austin, TX is asking to leave the car for 4 weeks and is not giving a loaner. This is turning out to be the worst decision I have ever made. I plan to trade it in once the AC is fixed. Never buying an Audi again.

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3k miles = 5k kms.........coincidence? just took it into dealer today, hope they diag and repair soon.

did they diag yours already to give the 4 wk leave? waiting for parts? what is the issue?

the flyin said:

3k miles = 5k kms.........coincidence? just took it into dealer today, hope they diag and repair soon.

did they diag yours already to give the 4 wk leave? waiting for parts? what is the issue?

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Took the Q4 to the dealership today morning. The pressure sensor needs to be replaced. They are ordering it now and quoting a lead time of 2-3 week. I got the car back as I did not want to leave my car there for 2+ weeks.

Max said:

Took the Q4 to the dealership today morning. The pressure sensor needs to be replaced. They are ordering it now and quoting a lead time of 2-3 week. I got the car back as I did not want to leave my car there for 2+ weeks.

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i dropped my Q4 off at dealership yesterday aft.......hoping to hear diag results very soon.
given its the same pressure sensor with similar leadtime I wont be leaving it there either.

countless reports of the pressure sensor being faulty between id4 enyak and q4

the flyin said:

i dropped my Q4 off at dealership yesterday aft.......hoping to hear diag results very soon.
given its the same pressure sensor with similar leadtime I wont be leaving it there either.

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Hi Flyin, did you hear back from your dealer, what was the diagnosis?

Max said:

Hi Flyin, did you hear back from your dealer, what was the diagnosis?

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no results yet...........Ill be calling tomorrow 📞, shall post when I know.

update......dealership has found wiring issues possible caused by wildlife. they can repair the damage and replace a sensor as a matter of course.
given we took the Q4 out to the seasonal camping spot thats full of rabbit/gopher etc etc and the lack of a/c issue was noted on the trip home after several days at campground the diag is very plausible. I should add the a/c system worked perfect previously to the trip.

dealership has pics of the damage Ill post.