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Discussion Starter #1
To elaborate my wife and I are experiencing our first summer in Phoenix and the AC although well charge just can't keep up especially if you are at a stop. I first replaced the cabin filter and it got much better. Then recently only a couple weeks later it seems to be not cooling enough again. So I thought maybe I will just run it without the cabin filter for a day or two to see if it's an air flow issue. After I pulled the filter and put the cover for it back on without reattaching the vents I turned the Treg on and cranked the AC. To my surprise the air as it comes from the ducts down below was very hot. I assume since I didn't yet attach the vents that it was taking the outside air and instead of running it over the condenser coils it was blowing straight to the floor. So I put the vents on and to my surprise, the passenger side blows hot air and the drivers is cold. Now I never ride in the passenger side of my car, usually my wife does. I assume if it was blowing hot she would have said something.

So in conclusion either I just now did something causing it to blow on on the passenger side or it's always been this was and this is why my AC can't seem to keep up.

Thoughts?
 

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If you run the A/C (or even just the blower for that matter) without the cabin filter in place, you're risking clogging up the fins of the evaporator and/or the heater core with dust and debris. Also, unless your cabin filter is a decade old and is itself full of leaves and dust, it can not possibly restrict your airflow - at least not to abnormal levels. And it definitely can not cause your A/C to not cool enough, because obviously the cooling capacity is not or only marginally affected by the air passing through it (within reasonable limits), and can not cause your vents emitting air with different temperature than desired, either.

Instead you might have a problem with the A/C system itself, or the with the vent system. For ex. you might have a small leak and the A/C could have less than ideal amounts of refrigerant in it, which in turn would limit its cooling capacity below that of the maximum. Or there could be a problem with one or more of your temperature flaps, and the system might not be able to mix and direct cooled and hot air in the desired ratio. Or you might have a problem with the cabin temperature sensors, and the system might think that it's a lot colder in there than it actually is, and because of that not direct that much cold air in it, or direct it to just one side, and not to the other.

You need to read the fault codes first, possibly run a re-calibration of the flaps, check the cabin temperature sensor readings (vs the actual ones) in the live data, and go from there.
 

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Discussion Starter #4
If you run the A/C (or even just the blower for that matter) without the cabin filter in place, you're risking clogging up the fins of the evaporator and/or the heater core with dust and debris. Also, unless your cabin filter is a decade old and is itself full of leaves and dust, it can not possibly restrict your airflow - at least not to abnormal levels. And it definitely can not cause your A/C to not cool enough, because obviously the cooling capacity is not or only marginally affected by the air passing through it (within reasonable limits), and can not cause your vents emitting air with different temperature than desired, either.

Instead you might have a problem with the A/C system itself, or the with the vent system. For ex. you might have a small leak and the A/C could have less than ideal amounts of refrigerant in it, which in turn would limit its cooling capacity below that of the maximum. Or there could be a problem with one or more of your temperature flaps, and the system might not be able to mix and direct cooled and hot air in the desired ratio. Or you might have a problem with the cabin temperature sensors, and the system might think that it's a lot colder in there than it actually is, and because of that not direct that much cold air in it, or direct it to just one side, and not to the other.

You need to read the fault codes first, possibly run a re-calibration of the flaps, check the cabin temperature sensor readings (vs the actual ones) in the live data, and go from there.
The refrigeratent is full, I checked it. It's gotta be a blend door issue. I do not have a Vagcom cable but do have OBDeleven app and dongle and with that comes a lot of the same functionalities. But playing with it last night I was not able to find where to calibrate the flaps. Do you know where I can get the information to do that?
 

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Yes, OBDevelen should be good. Check the cabin temperature sensor readings in the HVAC controller, whether they all return valid data. Flap adaptation (endpoints learning) is in Basic Settings, Group 001.
 

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Discussion Starter #6
Yes, OBDevelen should be good. Check the cabin temperature sensor readings in the HVAC controller, whether they all return valid data. Flap adaptation is in Basic Settings.
I will see if I can find that. I do have 3 codes I cannot clear (see attached) but I can't see how any of these will cause the passenger (right) side to not blow cold or as cold as the drivers side. I Rand the flap calibration a few times to see if it would get better, it's hard to say if it did anything.



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Discussion Starter #7
Yes, OBDevelen should be good. Check the cabin temperature sensor readings in the HVAC controller, whether they all return valid data. Flap adaptation (endpoints learning) is in Basic Settings, Group 001.
Here are the temps I'm reading.



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You seem to have a refrigerant temperature sensor issue. That should be your main problem. The loss of refrigerant fault code is most likely only triggered because of the sensor issue, not because of an actual leak.

There's also a >10 degree difference between the left and right cabin temperature sensor readings, which is a lot. Provided you measured these with the A/C actually being off, because if not, that obviously could result in such difference, if cold air is distributed unevenly.

The usual procedure to check temperature sensors is to shut off the engine and leave it standing for a while (possibly even overnight), and then check what readings the sensors return. If the car has been standing still for a while (and the sun isn't shining on the car either), all temperature sensors should return the same readings, which all should be the same or very close to ambient temperature. And the ones that don't do that but return different readings are obviously faulty ones.
 

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Discussion Starter #12 (Edited)
You seem to have a refrigerant temperature sensor issue. That should be your main problem. The loss of refrigerant fault code is most likely only triggered because of the sensor issue, not because of an actual leak.

There's also a >10 degree difference between the left and right cabin temperature sensor readings, which is a lot. Provided you measured these with the A/C actually being off, because if not, that obviously could result in such difference, if cold air is distributed unevenly.

The usual procedure to check temperature sensors is to shut off the engine and leave it standing for a while (possibly even overnight), and then check what readings the sensors return. If the car has been standing still for a while (and the sun isn't shining on the car either), all temperature sensors should return the same readings, which all should be the same or very close to ambient temperature. And the ones that don't do that but return different readings are obviously faulty ones.
Ok, so I let the car sit in my garage for about 2 hours and checked again with no fans or AC running and here is what I got. All the temps are fairly close aside from the coolant temp.

So then it seems the temp sensors are all fine, wouldn't you think?


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Yes, that leaves the temperature flaps as culprits, if you get different temperature air from different vents, despite all sides being set to equal in the controls. And of course you have the problem with the refrigerant temperature sensor, which could cause sub-par level of cooling or even getting the A/C disabled completely, because of the false loss of refrigerant fault.
 

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Discussion Starter #14
Yes, that leaves the temperature flaps as culprits, if you get different temperature air from different vents, despite all sides being set to equal in the controls. And of course you have the problem with the refrigerant temperature sensor, which could cause sub-par level of cooling or even getting the A/C disabled completely, because of the false loss of refrigerant fault.
I just did another scan after the car was in my garage all day and the only code now is just the air quality sensor. So I think I'll order that and the blend motor for the passenger side.

Thanks for the help.


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The air quality sensor of no importance in regards to temperatures. It's only used by the auto-recirculation function to switch between fresh air intake and cabin air recirculation settings automatically. Only makes sense to replace it if you're using the auto-recirculation function.

The other codes not being present doesn't mean much, as those are kind of codes that will not be triggered immediately, but only after a while. So, it would make sense to do another scan later, preferably after a longer trip, because they just might surface again.
 

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The air quality sensor of no importance in regards to temperatures. It's only used by the auto-recirculation function to switch between fresh air intake and cabin air recirculation settings automatically. Only makes sense to replace it if you're using the auto-recirculation function.

The other codes not being present doesn't mean much, as those are kind of codes that will not be triggered immediately, but only after a while. So, it would make sense to do another scan later, preferably after a longer trip, because they just might surface again.
I do use the auto recirculation feature only because I use Auto for the climate control almost exclusively and turning the recirculate button on turns Auto off.

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