I have a 970.2 2014 GTS

Although the fan is working, the AC on the two driver side front vents is not cold (not even cool) whereas the passenger side is cold. Running the heat will have a similar temperature bias with hotter air on the driver side. Not sure if the control unit is faulty or if the servo motor that controls the blending is faulty. It was working perfectly at lunch but not 4 hours later. A restart and playing around with fan and temperature controls made no difference. Is this something the Durametric could help diagnose?

 

I had a similar issue but with heat. Turned out to be my heater control valve. Not sure if this helps?

Here’s the post about my issue in case it helps:
https://rennlist.com/forums/panamera...rior-heat.html

 

It could be that your Freon level/pressure is out of spec? I experienced the same problem as you described earlier this year in conjunction with a A/C condenser leak. I thought it may have been one of the HVAC air mixing control solenoids. Prior to service of the A/C condenser, the Porsche service advisor commented that HVAC problems can be attributed to incorrect Freon levels (a quirk of the Panamera or Porsche). After the A/C condenser leak was repaired and system recharged to spec, the driver's side air mixing control was functioning properly.

Durametric did not show any problems prior to repairs.

Have your A/C system serviced by a qualified Porsche mechanic.

 

The week prior I heard an uncharacteristic hissing sound from under the dash after the engine was turned off. Didn’t think anything of that because some systems do make noise after turning off the engine. So maybe it is low Freon as you suggest.

I looked at the online Porsche manual for dash removal to get at the servo motors,14 of them in my case. It’s doable but not looking forward to that and I’m sure the dealer charges much $$$. So will have the Freon checked next.

 

That happened to my 14 4s 2 years ago, freon charge fixed it since

 

I added 4 ounces of Freon and now get cold air from both the driver side and passenger side vents. I used the auto parts store charging kit with built in gage of unknown accuracy. I’ll recheck it with a more accurate gage before the start of the hot weather next year.

Thanks for your help!

 

970.2 4S with 4-zone climate control.

Noticed today that both my driver’s side air vents (closest to the rear view mirror + driver’s side of the PCM head unit) are blowing noticeably warmer air compared to the passenger vents. Passenger side and rear vents are blowing cold. Also hearing a new faint “hissing” sound when the system is running. Hissing goes away if the system is turned off (turning the fan all the way off). Thoughts and help?

 

This could be a possible temperature sensor problem. If you have a PIWIS or Durametric you can read the temperature setting of the driver side sensor and check if it reads correctly (little round eye in the shiny trim next to the steering wheel) An easy diagnostic check is to put the driver side in Lo by lowering the temp till it reads Lo then seeing if it blows cold air. If it does, the temperature sensor needs replacing. The good news is, that this is a cheap part ($65 if I remember correctly) and easy to replace

 

Did you check and top off the freon as mentioned earlier in this thread? That seems to have fixed this issue for others

 

Just fyi, putting in refrigerant will fix your cold vent problem, but if you did this without checking the ac system pressure, you are asking for breaking of the ac in not too distant future. Then it will be an expensive fix.
Before you put in refrigerant, make sure the system needs a charge. If it needs a charge, chances are there is a leak in the system. PIWIS can help tell you all these things. If you are not sure, take the car to a good ac indy shop (who works on porsches), and they will evacuate ac, pull vacuum, make sure no leaks, then will charge it up to spec.
Amount of refrigerant depends on ambient temperature outside car, and ac has to be in specific state. It is not just a simple (I squirt some from that walmart can) type of a deal, if you are looking to have it done right.
If that does not fix your issue, it could be the sensor, it could be the air mixing flap servo motors (known issue on porsche cars).

 

No need to remove the dash to get at the servos. All are accessible from below. Servos all throw codes, so if you can get diagnostic equipment you can see if it is a servo. The car has two mixing sections, right and left side. From there it splits to multiple vents, up, down, middle rear and under seat. The temperature mixing valve is controlled by the temperature sensor on each side. If you lower the thermostat till it says low on one side and it isn't cold, then the mixing valve or freon may be the issue. If you lower to low and suddenly it is cold, then the temperature sensor is at fault. If you have no air flow on vents that are open with the wheel, then the vent servo is to blame.

 

Another warm day today so spent some time checking the A/C again.

My observations:

1. Driver’s side vents definitely blowing warmer.
2. Passenger vents are blowing ice cold.
3. Rear passenger side is ice cold.
4. Rear driver’s side is cold but subtly warmer than rear passenger side.
5. There is a faint “hissing” sound when the system is on (this is NEW). As soon as the climate control system is turned all off this hissing disappears.
6. Even when the system is turned to “LOW” the above symptoms persist.

I have a PIWIS 2 and ran a diagnostic on the 4-zone climate control servo motors. All checked okay. Also, no fault codes related to the A/C or climate control module.

Car going to dealer next week for unrelated issue. Service Advisor says they will pressure test the system, add some UV dye, and then recharge as needed. Can then use UV detector to look for leaks. Make sense?

Anything else I can do in advance to help diagnose the problem?

Thanks!

 

A/C recharged and blowing ice cold again! They pressure tested system (low), recovered refrigerant, added UV dye to look for leaks (none detected yet), and then recharged the system. The “hissing” noise is also gone. No charge for this work. Will check for A/C leak (UV dye test) when I return.

Hope this helps some else who might experience the same symptoms.