So we did a whirlwind road trip to Portland today, car ran beautifully, suspension handle excellent, but on the return trip I started feeling hot. (it was 60 degrees outside)
Notice there was very little air flow from the vents, cranked up the fan - noise got louder but no more air? back vents didn't have any flow either.

Got home unloaded the car got the mail and broke out the iCarSoft POR II to see if I could get anything from it (I'm really thinking about getting a icarscan or piwis II, need a better tool)
anyway, scanned the AC shows a code C1209D I believe, played with the fan controls again and air was coming out? started it up and cold air came out - not sure what to make of it.

anyone have a clue?

 

Found it finally:

Gateway control unit fault value received or signal implausible

Doesn't really say much except one of these conditions was met:

Receiver detected a fault value sent from transmitter
or
Receiver detected a value range fault from transmitter
or
Coding of transmitter and/or receiver doesn't match vehicle
or
Programming of transmitter and/or receiver doesn't match vehicle.
Effect
Receiver uses backup functions
Functions are either partially or not available in control units.

No diagnostic direction is given...
​​
I think this code looks familiar. If it is then it went away after the AC recall. Otherwise it was quite often there.

 

Thanks, I'll have to do more digging to try and understand that

 

Couple more details, we did stop a couple time, once to eat and twice to shop, but i didn't pay attention as to whether or not the air was blowing correctly.
I notice after I got home and moved the car into the garage there was a fairly large puddle of water where the car has been siting, something I have not seen before (it's extremely dry here 25%RH or less, very humid in Portland)
I wonder if my coils froze up? I basically turned everything off for the last couple hours of the drive and cracked the window to get some cool air in.

 

I'll bet that was just condensation from the A/C system - I get it regularly on all of my vehicles.

 

If the fan does not blow, very likely it is the regulator (in parts catalog, item #7).
If you see water under car, it likely means your ac is working, cooling, so my first guess would be are the stepper motors that control temp mixing in cabin, do they work ok. Over time, in porsches and other cars, there are stepper motors that actuate mixing flaps, that mix cold/hot air with ambient air, that goes into cabin. When stepper motor goes bad, mixing flap does not open or close, and it appears ac is stuck in one mode, often warm.
One way to pd is to test the actuators, but not sure if your tool can do that. My durametric can do this on CTT, but not on PTT.
There are so many gremlins living in Porsches when batt charges are wrong, it may be worth while to disconnect batt for an hour, then reconnect (resetting system).
Thats my guess.

 

Yes, it is possible that the coils froze. Similar situation happened to me during a long and hot road trip. The blower was working but HVAC flaps were not working... seem to be blocking airflow. Pulled over, turned off the car for a bit and reset HVAC fault code. A/C worked fine for the rest of the trip. May have been sufficient time to defrost the coils sufficiently? I think this was the first indication that I had an A/C leak. On a subsequent road trip, the A/C was blowing only warm air. Had to find service ASAP because we were headed to +90F climate. Porsche service tested the A/C system but could not locate the leak and topped-off the refrigerant. The next year, the A/C refrigerant was low again and the HVAC flap controls malfunctioned. Local Porsche service found a slow leak (puncture) in the condenser. After the condenser was replaced and refrigerant back to spec, HVAC flap controls worked normally.

The service advisor stated that the HVAC controls are sensitive to having the correct refrigerant level. I have since installed a front grill to minimize damage to the radiator and condenser from road debris.

 

Thanks dudecs, that confirms that my thinking wasn't totally off.

 

Good news bad news, check the level of my refrigerant, it's fine.
I think my freezing theory is still correct as I have had no issues since then, but why it got frozen over I don't know since the Freon wasn't low.

 

As you might already know if it is overfilled it can also freeze over. (You didn't share that any refrigerant was added but just in case you did add some).

Also just remembered it can also freeze over if there's no air flow. (Which came first, the chicken or the egg, air flow stopped then the coils froze over, or coils froze then air flow stopped)...

 

Well, that is good news. If you have an appropriate ODBII reader, see if there is a fault in the HVAC system. There was a passive fault and I never did figure out what the fault meant. Hasn't occurred again.

UPDATE: Re-read your original post and saw your fault code. C1209D was the same fault that I had experienced.

 

nothing added, merely checked, I didn't even by any R134a.