jroczniak

2011 A6 3.0

4 days ago AC worked fine - almost too cold as usual.

Yesterday - warm/hot air only.

I hooked up just the valve/gauge part of an AC recharge unit and the pressure sits at 100% continuously - I know that usually if it is undercharged when the compressor kicks on it will usually drop down.

Any thoughts - I have not looked at the compressor yet to see if it's actually turning on or not. I hope I can see that semi-easily.

I am going to check fuses tonight.

Sverige

It sounds like a G395 aircon pressure sensor problem. A very common issue (I'm halfway thru changing mine in fact on an '07 Allroad)

jroczniak

Thanks I will do some research around that.

Sverige

Ok, I can't say for sure that's the problem, but for sure I've seen many threads talking about warm air from the vents with the cause being cited as the G395. There's a service bulletin from Audi about it too.

I bought my replacement on eBay for around 25 British pounds (worth approximately diddly squat since Brexit!) so it doesn't have to be an expensive job to fix. I'd have swapped mine already if it wasn't Provo g to be tricky to get the front bumper off.

jroczniak

It looks like it throws a code when that sensor goes so I am going to check that first.

Thanks!

jroczniak

I did look and I have the 00256 code for the G395 pressure/temperature sensor! I will work on replacing that first.

Thanks again!

Sverige

That's good news. I've now changed mine and it proved to be a surprisingly easy job. I've seen people claim they can change them without moving the front bumper at all, but they must have wrists like ballerinas. I took out the top three fixings from the front bumper, plus the 10mm nut securing the bumper to the "fender" and the three t25 torx screws low down inside the wheel well, then moved the front bumper forwards a few inches and released the headlamp washer union and bunged the pipe to stop it dripping.

Next the bumper can come forwards further (I left the other side 10mm nut in place) and the bracket directly above the G395 gets unscrewed and removed then the shroud covering the electrical connector can be released with a small torx screw (hard to see).

Unbolting the G395 and re-fixing the new one takes just minutes and there is no need to de-gas the system. I re-used the same O ring which was already on there as it seemed fine.

Looks complicated when you write it out, but a pretty easy job.

jroczniak

Awesome, I am going to do it this weekend. I found this entry on an A5 forum (with the 3.0) engine and it looks to be the exact same.

Air con pressure sensor G395 replacement - Audi A5 Forum & Audi S5 Forum

I did order the 24mm crowfoot spanner to help with removal so I do not have to remove the bumper.


Thanks again!

Sverige

Ps. Don't over torque the new one when fitting. It is just soft aluminium

Sverige

Ok. Sadly not exactly like that on the A6. Not unless your A6 is very different to mine, and I assume they're all made the same in Germany. You will find once you've removed the top cover panel you can only just see the G395, which is fitted with a horizontal orientation, not vertical as it appears to be in that pic of an A5. There is a supporting bracket for the front bumper which needs to be taken out before you can get to it, plus the shroud I mentioned before.

As I say, at least one fella claims he did it without taking the bumper off and with that crowfoot spanner you will stand a chance, but it's going to be awfully tight.

Good luck though, you might be much more of a mechanic than me (wouldn't be hard!)