Hi @tom66 .
If I recall correctly, VW recommend a A/C service every two years.
It conveniently ( for the dealers ) sits between the recommended brake fluid change every two years !.
So, first A/C at two years, then first brake fluid change at three years, then every two years after that.
Either way, when you present the car for it annual service, you will get stuffed for one or the other, that's how they roll !.
On the A/C service I think they replace the cabin filter and check the cooling gas pressure.
Just a though, have you had your cabin filter replaced ?.
If this is restricted, could this be the reason why you now find yourself having to use a higher fan speed now ?.
Worth considering first maybe.

 

At the end, what was the issue? I have the same problem. Thanks!

 

I just got the car re-gassed by someone that knew what they were doing and it worked fine.

The GTE Mk7 uses R134a which is not too expensive to gas with. Charge was £50 for a mobile service guy to come out and do the work and it took a few minutes. If it is a Mk7.5 onwards I believe it uses R1234yf which can cost £130+ to have serviced.

Make sure whoever gases it uses an air conditioning oil that is suitable for hybrid air conditioning systems. Most are, basically the oil must be non conductive as it might cool the windings of the compressor, which run at battery potential. It's possible, if old PAG oil is used from a non-hybrid (most systems recover and reuse the oil) that it can leave conductive residue in the compressor, which could lead to catastrophic failure.

Weirdly I first had the issue with the car, had it gassed at a garage, but it was September when I got that done, didn't seem to be much better but weather was getting cooler. Come summer time its struggling again so I used a mobile service and got him to come out on a hot day, blowing ice cold after he did that. And that lasted another year without issue. So I don't know why the first time it didn't work so well, maybe that garage ripped me off and never did the work properly, it's September he ain't gonna notice if it's got enough gas in it!

The aircon does cool the battery pack on these so even if you don't want a cold car you should get it done to preserve the lifespan of the battery.

 

Thanks Tom!
I've been experiencing an issue with my GTE for the past year and a half, particularly during last and this summer. Half of the car cools properly while the other half remains warm. Although my car is still under warranty (from 2022), I plan to take it to VW for a check-up within the next two weeks. I find it quite unusual for a new car to have this problem.
Once I get the issue resolved, I will provide an update and share the information. Hopefully, it can be helpful to others facing a similar situation.

 

Just had my 7.5 with the newer type refrigerant done and it was £103 with VW in Leeds. Same time as having the interim service done.

It wasn't desperately bad, but they said it was running about 7 degrees out the vents and they recommend it to be about 4.

As usual they should recover all the gas out, do a vacuum test and then refill with oil and refrigerant. UV dye is also sometimes added so assist with leak finding but it's not required. Mine had the UV dye too.

 

I have a Passat GTE 2017 67 plate and I just noticed on a warm sunny day (23 C ambien temp) that on AC on max, recirculation on and set to LOW temp on sync mode it just doesn't do anything. Like the temperature of the air blown from vents was above 20 C and should expect close to 4 if working properly. I bought one of those top up kits from Halfords for R1234yf gas to check the pressure and top it up if needed but the gauge showed that the system is full (spot on as it should be) and didn't need any gas. I wondered what could be the reason for the AC not to work. Also did a VCDS scan and no faults there at all. Could it be low ambien temperature that prevents from switching the compressor on but on a sunny day inside the cabin gets way warmer and you need AC even if outside is just 23.

 

No, that sounds like a fault to me. Could be a duff temperature sensor causing the compressor to cut off early but I had the A/C in my car blowing ice cold even when it was 15C outside for instance.

 

Thanks for the advice. Will try to check sensor readings with my VCDS tool and see if they are any good. Will keep this updated until resolved.

 

A quick update from my own investigation today.
System is full with gas - mechanical gauge shows 50 PSI and VCDS shows 4.6 bars (can't check the oil quantity though)

The electrical compressor is working, switching on and reving up to 3000 rpm
The AC system is pulling around 1.0 kW/h energy while working on MAX (on the low side, looks like no decent load)
On a 13 C outside temperature, on AC to MAX and LOW temp setting and recirculation on, the air temperature from the vents was around 15 C only.
VCDS shows no errors on the 08 HVAC module for the Climatronic and on any other modules from the autoscan (a part from one error on the Instrument cluster module which is not related to this)
The only sensors that I couldn't understand what temperatures they measure, what is their location and what values to expect are 5 temperature sensors named: Temperature sensor 1 ; Temperature sensor 2 and so on to Temperatiure sensor 5. Now two of those sensors' readings were way out of any normal temperatures showing both the same value of 13067.0 C and not changing at all. Those are Temperature sensor 4 and 5. I will attach a photo. Any idea what these sensors are for and why the values are like this?

Everything else looks fine to me and I can't understand why it's not cooling the air inside at all. I was thinking if the compressor is mechanicaly worn out or there is a stuck valve somewhere or a blocked pipe. To me it looks like a mechanical fault rather electrical because there are no faults registering with the AC module and the system is operating but not achieveing temperatures.
The car has 79000 miles on the clock.
I think the next step would be to take it to a VW garage for a repair. Before I do that I wanted to get an idea of what is wrong with it.

 

I think if compressor is running at 3000rpm you would expect more than 1.0kWh/h on the dashboard (for simplicity, 1kWh/h is the same as 1kW... Germans being weird with units...)

I would expect dashboard to read around 2.0kW in this weather just remembering from when my car was working. The car itself has a base consumption of 400W for all of the computers, brake booster, lights, etc. so around 1.6kW left to the air conditioning system.

I do remember that my A/C speed did not go much above 3000rpm. Which makes sense as it is likely a similar system to a combustion car, they possibly use the same compression mechanism and just drive the shaft with an electric motor instead of the engine. Most ICE A/C compressors will be declutched when you go above 3500-4000rpm to protect themselves.

It sounds like it's possible the compressor shaft is loose/broken in some way - can you test both sides pressure - you should see one side change in pressure when A/C turns on and off. I would guess that would be a new compressor needed if so. Probably quite expensive at VW so I'd find a HEVRA garage to do it. May also be worth checking the pressure data in the VCDS log - think the car has at least one sensor for that.

It sounds like the temp sensors are probably nonsense, possibly not fitted to your car, if A/C temp data was not valid I'd expect compressor to stay off.

 

The dashboard was showing 1.3 kW total consumption after settling down for a while but 0.3-0.4 kW is for the rest of the car so I meant 1.0 kW for the AC itself. And also it peaked at 1.6 kW before settling down to 1.3 kW but I was expecting it to peak up to 2.0 or 2.5 kW at least.

I will run it again and look at the advanced measuring block to see if pressures change and how. But yes my fears cline towards mechanically faulty compressor too.

Thank you for all the help and advice again Tom, much appreciated.

 

OK, I don't know what is happening to this AC but when I went to test it again with the VCDS to see if the pressure is changing when the compressor runs, the AC started to cool as it should this time. What I discovered was that before switching the AC on the pressure reading (I assume on the low-pressure side) was reading a constant value of 4.6 bars (not changing at all). When I turned the AC on, that pressure started to rise. The highest I saw it going to was up to 9.0 bars but as it was running was changing from 5.8 to 8.0 bars. And the temperature from the vents got down to 4.7 C degrees as lowest I have seen so far. But it wasn't a steady value, shortly after that went up to 5 and then 6 C. It could be that I haven't used the AC at all since I bought the car last September 2023 and it needed to run the system for a while to get the oil around the system and work as it should. It could also be a stuck valve that eventually got working or a tiny block in the system, who knows? I will just monitor it from now on and turn it on every now and then just to circulate the oil and gas around.

 

Did your A/C carry on working ok?

I've got seemingly the same issue, I don't have VCDS but the symptons match closely. The compressor switches on and off at the touch of the button, the gas is full; was 340g just been topped up to 500g.

The air conditioning doesn't cool on command but has periodically kicked in of it's own accord a handful of times and when it does, cools down to around 4 deg. If the A/C is switched off and then straight back on again once it has been operational, it doesn't carry on working. The electric compressor, while not overtly noisey, isn't the quietest thing in the world, so whether this is the culprit part, I don't know. the symptoms suggest a sticking valve of some sort.

Reluctant to take it straight to a garage as the likely response is; "Need a new compressor!" If that didn't fix the issue, I would be very miffed to say the least, as they certainly don't have a habit of reimbersing you for parts and labour that wasn't actually needed.

Any info relevant or advice will be much appreciated. Thank you.

 

Sounds like there could be some contamination maybe in the system. If it plays up again, may be worth getting gas and oil drawn out and refilled. Expensive, but if it seizes the compressor, that will make it look cheap in comparison...

 

I'm having a similar issue with my 2015 Audi A3 e-tron with 60k miles. Its the same as the GTE underneath.

The air con is blowing hot air and as a re gas didn't fix the system, and I can audibly hear that the compressor is not kicking in (previously it was making a horrific buzzing noise), I'm exploring the option of replacing the compressor. I'm trying to get hold of VCDS to diagnose it further myself.

One question to ask, does anyone know if a replacement compressor needs coding to the car? I plan to buy a used compressor from a breakers yard and replace it.

My plan is to get the system degassed, and then drop the compressor from the bottom of the car. It seems that the bolts should be sufficiently accessible if the bumper headlight and probably the wing is removed - all bolt on and bolt off parts so can't be too bad.

 

The compressor won't engage if the system has no pressure, VCDS or OBD-11 should allow you to see system refigerant pressure and any fault codes.

 

Thanks, I noticed the pressure sensor when looking into the HVAC system diagrams.

The system is degassed at the moment because the garage who did the re gas didn't want to charge me for a re gas (as when they gassed it up, the compressor still didn't kick in). But that is annoying as it might get in the way of my diagnosis.

 

Had the codes read and one was UO46C00 - Invalid data received from Electric A/C compressor control module. Does anyone know if the A/C compressor control module is built within the A/C compressor? (As opposed to the HVAC control module). Many thanks for any info supplied.