A3 2015 8V air conditioning issue

DLH21

Registered User
Hi everyone,


2015 1.4tfsi A3. I noticed this week that the air conditioning is not coming on when I press the AC switch and have now learned that I probably should have been running it all year round which is news to me but lesson learnt! When I press the air conditioning button, the light comes on but as soon as I release it, the light does not stay on. I can also tell that the compressor is not even engaging. If I use start/stop when I press AC the engine does not come on which I know it used to.

I've looked through this forum and seems like this is normally something quite catastrophic like the condensor holed but I there's no damage to that and after taking the car to quikfit this morning, they confirmed the air con gas pressure is normal and the fuse is fine so they think it is an electrical issue somewhere but recommended taking it to Audi. I noticed on other forums that the G65 sensor can cause issues, but can't tell if my A3 has one of these. I guess this would be a good place to start so trying to sort out a VCDS diagnosis locally but does anyone have any other helpful advice on where to go next that would really help!
 

zac7654321

Registered User
same year car, same issue with the a/c this morning...

have you had the chance to find out more about the problem in the meantime?

Sent from my SM-A530F using Tapatalk
 

DLH21

Registered User
Hi zac,


I had almost given up on this forum to be honest. Seems like most people interested in how to ruin their car with mods than actually repair it...

I managed to get the AC working by unplugging the G65 sensor, it runs fine that way but not especially cold. I checked power going to the G65 sensor and it was reading 10V, thought it might be 12V because the previous A3s are 12V but then realised it’s a different sensor to that. Checked the duty cycle reading from the sensor with a multimeter and it was reading 100% all the time, which I think implies that it thinks the system is over pressured (which it isn’t)

I’ve now ordered a new G65 sensor from eBay (genuine Audi OEM of course). Waiting on that to arrive.

Best thing to do is to remove the low side refrigerant cap (it has an L on the cap) and stick a pen or screwdriver into the top of the schrader valve to confirm if there’s any pressure as you really have 3 options 1. No charge at all (probably condenser damaged or leak elsewhere) 2. Low pressure - likely either a G65 sensor failure or genuinely too low pressure to operate the system. 3. Normal pressure - likely a g65 sensor failure.

I know it’s hard to tell from just pushing the schrader valve for a half second but I could tell my system had good pressure from doing that alone, which made me concentrate on the G65 sensor.

hope that helps
 

zac7654321

Registered User
cheers pal, will tey to re-gas the system first as now 5y old and don't know if they ever re-gassed it before.

i'll update once done

Sent from my SM-A530F using Tapatalk
 

Ormesome

Registered User
Hi zac,


I had almost given up on this forum to be honest. Seems like most people interested in how to ruin their car with mods than actually repair it...

More like this car has been around since 2012 so that’s 8yrs of people on this forum answering the same thread posts that come up weekly and some daily. If you had searched for your problem you would have found a load of advice. If you search my thread posts you will find I posted regarding the same symptoms you have. Btw, I would paste a direct link for you but I’m way too busy ruining/modifying my car
 

DLH21

Registered User
cheers pal, will tey to re-gas the system first as now 5y old and don't know if they ever re-gassed it before.

i'll update once done

Sent from my SM-A530F using Tapatalk
Just wondering did this work for you? I changed out the G65 sensor but no joy, so I have a feeling it needs recharged, wouldn't be the first time I should've known better than to go to Kwik fit.
 
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DLH21

Registered User
More like this car has been around since 2012 so that’s 8yrs of people on this forum answering the same thread posts that come up weekly and some daily. If you had searched for your problem you would have found a load of advice. If you search my thread posts you will find I posted regarding the same symptoms you have. Btw, I would paste a direct link for you but I’m way too busy ruining/modifying my car
I searched and found nothing on the 8V, which is why I was asking whether 8V or 8P were the same in the first post. Every other thread is about condensor failure which I don't have because there's still some pressure in the system. So cheers for the useless post pal.
 

zac7654321

Registered User
Just wondering did this work for you? I changed out the G65 sensor but no joy, so I have a feeling it needs recharged, wouldn't be the first time I should've known better than to go to Kwik fit.
haven't done it yet due to the "pandemic" but will update once done

Sent from my SM-A530F using Tapatalk
 

Ormesome

Registered User
I searched and found nothing on the 8V, which is why I was asking whether 8V or 8P were the same in the first post. Every other thread is about condensor failure which I don't have because there's still some pressure in the system. So cheers for the useless post pal.

Mine wasn’t condensador failure and I showed the same symptoms as you.......”pal”
 

DLH21

Registered User
Mine is sorted, as suspected, just needed a re-gas, 60€

Thanks for letting me know, I have had mine regassed too and now the AC light comes on and stays on but still no cold air... Now I'm at a total loss as to whats going on. Time to take it to Audi I think.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Thanks for letting me know, I have had mine regassed too and now the AC light comes on and stays on but still no cold air... Now I'm at a total loss as to whats going on. Time to take it to Audi I think.

Why on earth would you do that?
Any indy can diagnose a AC issue and probably less than half the price. You can get main parts for around 120.00 on Euro, Audi would charge you at least 400.00 just for the part alone.
 

DLH21

Registered User
Why on earth would you do that?
Any indy can diagnose a AC issue and probably less than half the price. You can get main parts for around 120.00 on Euro, Audi would charge you at least 400.00 just for the part alone.
Unfortunately there aren’t too many vehicle air conditioning or even Audi specialists my way (Aberdeen). Without knowing what the issue is, I can’t even begin to make a decision on how to get it repaired so taking it to Audi seems the only choice
 

DLH21

Registered User
As a final update for this -

I had the car regassed and after a couple of days the air blew warm and then the air conditioning pump would not even engage again (light did not stay on), I then went back to the garage and it was regassed again as their machine could not find a leak when pulling a vacuum through the system. But again, the air con blew warm a couple of days later and again the pump would not engage another day later.

I visited my family away from Aberdeen and had an opportunity to take it to a auto electrical specialist. Within half an hour they knew there was a leak in the system but hard to see where. They spent a bit more time on it (about another hour) and came to the conclusion the most likely cause of the issue was the condensor which despite having no major damage was generally corroded all over, probably because of the sea air and salt on roads for many months of the year in Aberdeen.

The condensor was replaced, system regassed and also needed to replace the G65 sensor which I'd already bought. Altogether including the diagnostics it cost £390. Once all that was done, the issue is now sorted for the past week so looks like its solved.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
My car is with my mate for the same thing, well dont know the issue yet as my AC light will stay on like it should.
I told him not to spend over 300.00 otherwise will just roll down my window lol
But 390.00 is a decent price, glad you got it sorted.
 

DLH21

Registered User
My car is with my mate for the same thing, well dont know the issue yet as my AC light will stay on like it should.
I told him not to spend over 300.00 otherwise will just roll down my window lol
But 390.00 is a decent price, glad you got it sorted.
If there's anything I can help with let me know and hope you get it sorted. My leak only appeared with a proper nitrogen pressure testing set up. Don't think they used any of the UV dye. I took it to Halls Auto Electrical, there is a branch not too far from you in Bristol. Good luck.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Yeah the guys at ATS only used a pressure test and said it was ok, maybe its a very small leak, but it must be very small as they said it was fine, but 2 days later I had no air con. Its super cold on the first 2 days then it just feels slightly cold, maybe slightly colder than outside.
Thanks really appreciate it, my mate is really good with all things.
I should know next week what the issue is.
 

DLH21

Registered User
Yeah the guys at ATS only used a pressure test and said it was ok, maybe its a very small leak, but it must be very small as they said it was fine, but 2 days later I had no air con. Its super cold on the first 2 days then it just feels slightly cold, maybe slightly colder than outside.
Thanks really appreciate it, my mate is really good with all things.
I should know next week what the issue is.
Funny because I had mine done twice at ATS too. I can't blame them, their machine only vacuum tests and obviously the leak wasn't big enough to be detected. With a vacuum test the pressure differentials are just too low compared to a nitrogen pressure testing system where they can apply much bigger differentials. ATS did the second regas for free and even offered to do a third for free if I needed to get work done and then regassed which was decent of them but not needed.

Sounds very very similar to what I had though, at least you know your compressor and rest of the system are probably ok.
 

CanadaA3wales

Canadian living in South Wales - Audi A3 8V 150BHP
Hopefully it's just a small leak if the AC light stays on like it should.
I'll let you know next week. Thanks for the advice
 
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