I've been the owner of a 2021 Scala for almost a year and a half by now, 45000km on the clock. I thought I would post this here to see if anyone have experienced something similar or have a hunch what could be the problem.

During a couple of seemingly random days in the last 5 months, the AC has just not produced any cold air at all. The display for the air con or the main infotainment doesnt show anything unusual. When the issue have occured, toggling the AC off and on again, or even restarting the car, wont help. Neither has trying to fiddle with any other related settings. Its usually not until the next day when I start the car that the AC is up and running again.

Other than those specific days, the cooling performance is very good.

Some additional info:

• I did an error code scan with an OBD2 device, but couldnt find anything.

• A couple of months throughout last winter, the AC was completely turned off (AC not really needed in Sweden during that time). I have since learned that you should "excercise" the AC and not keep it off during longer periods.

• I did the air con flap calibration twice, seemingly without effect.

• One warm day last week, soon after starting the car, I noticed that there were a couple of drops in cooling performance. After a minute or two, they disappeared and the AC stayed cool. During these drops, I think I could hear a faint change in noise tone from somewhere in front of the center console.

• I have a feeling that the issue is slowly increasing in frequency, but it's not very obvious.

I have read about coolant leaks, but would that really explain the behaviour? Wouldn't that make the AC loose cooling performance more evenly over a period of time?
Also, the coolant shouldnt really need to be refilled already, right? Unless there is in fact a leak, of course.

Is there anything I could investigate myself, without any special equipment, to help me understand what it could be?

Glad for any input someone could have on this matter!

The first thing I would do is get the AC checked to make sure there is enough refrigerant in the system. Modern AC refrigerants should have a UV dye in them so it's easy for a garage to check for leaks with a UV light source. Also in order to refill the system the garage needs to put it under vacuum, if they can't pull a vacuum then there is a leak.

A "visual check" will be a waste of money, better to ask for a check and re-gas.

On 04/09/2025 at 10:05, Aldfort said:

The first thing I would do is get the AC checked to make sure there is enough refrigerant in the system. Modern AC refrigerants should have a UV dye in them so it's easy for a garage to check for leaks with a UV light source. Also in order to refill the system the garage needs to put it under vacuum, if they can't pull a vacuum then there is a leak.

A "visual check" will be a waste of money, better to ask for a check and re-gas.

Thanks for your input. I've read about the process of searching for leaks but didnt know that the most coolants already have UV dye in them. How do I know if the coolant in my car has it?

1 hour ago, Vidde said:

Thanks for your input. I've read about the process of searching for leaks but didnt know that the most coolants already have UV dye in them. How do I know if the coolant in my car has it?

You don't but it's worth a look around the AC pipes with a UV light source. Generally the dye is green. A little green dye on the filling valve will be a clue. When you have it re-gassed then ask if they put dye in the refrigerant, if they say no then ask why not or find somebody who does, this is just basic maintenance stuff that a good garage would do.

Sounds very similar to the problem i had earlier this year and that was down to low coolant levels. Had the system regassed and some leak sealant added and everything seems to have been OK since

Here's a thread bump with more recent info. Does anyone recognize this behaviour?

Short recap: AC was every now and then not blowing any cold air. The next day however, it would be just fine.

Now, 9-ish months later, the AC never blows cold air at all anymore.

First, I had a look under bonnet and saw that the fan wasnt spinning and the compressor clutch didnt seem to be engaged.

Then I connected an OBD2 device, and Interestingly enough, I now get an error code: 262658 B10AE31 High Pressure Sender, No Signal.

Turns out the pressure sender is very accessible, so I began troubleshooting:

• I disconnected the sensor connector and looked for damage or oxidation, but it looked fine to me.

• I then measured the voltage to be 14.5V, with continuity between GND and chassis. Sensor should be 12V but I guess 14.5V is expected with the car running.

• Also, the LIN bus fluctuated between 6-10V ish, which I guess means traffic is going on as it should. A next step could be connecting a logic analyzer to see if the traffic is correct, but Im not sure that I could find out what the traffic on this LIN bus should actually be like.

• OBD reading constantly says 51 bar, which is of course not reasonable at all and is probably a value shown when no real value is available. Interestingly, the "outside temperature" value seems to behave in a similar way and shows -61C, however the dashboard reading of the outside temperature is fine.

Anyway, I figured that the sensor had simply given up and ordered a new one (NRF 38949) from autodoc. After installing it (and hearing a short and distinct "pfff" when unscrewing the old one) and clearing the error code however, nothing changed. Same error code, same behaviour.

I will now bite the bullet and take the car to the shop, but I fear that they will also not find the problem and instead start replacing expensive stuff that might not need replacing, so Im just throwing this post out there to see if someone recognize this and have some idea.

Cheers!

Sorry I am afraid , I may be wrong , I think like fridge they have compressor which has life, possibly after some years may need replacement if we want to use same fridge , I am not expert but ,my friend had similar issue for his jaguar finally changed compressor and all perfect after that .

thanks regards

Edited 21 June21 Jun by raky

When you take this car into a workshop that understands Auto AC systems, I'd think that they would fit their test manifold-gauges to this system and be in a position to start to work out what is happening - or not happening.

All VW Group cars tend to have a potentially faulty AC pressure sensor at some time or the other, either they end up leaking or just otherwise "not good".

On 21/06/2026 at 22:29, raky said:

Sorry I am afraid , I may be wrong , I think like fridge they have compressor which has life, possibly after some years may need replacement if we want to use same fridge , I am not expert but ,my friend had similar issue for his jaguar finally changed compressor and all perfect after that .

thanks regards

You could be right, but I hope you're not 😅

On 22/06/2026 at 10:24, rum4mo said:

When you take this car into a workshop that understands Auto AC systems, I'd think that they would fit their test manifold-gauges to this system and be in a position to start to work out what is happening - or not happening.

All VW Group cars tend to have a potentially faulty AC pressure sensor at some time or the other, either they end up leaking or just otherwise "not good".

Thanks, yeah they have tools that I don't to troubleshoot this, and as it is a VAG car they have hopefully seen similar issues before.