Porsche likes to hide some of these features. For the radio a single press of the button is just mute and it will come right back on again on next start, so pressing and hold turns it completely off. I haven't tried it myself, but have been told by others that long holding the fan button all the way down on the 981 does the same thing as it does for the radio

 

As far as I know, the HVAC controls are a safety feature. The car always want to make sure that you are getting circulated filtered air.

It will remember any setting you put it on except “off”. If you set it to off when you restart the car it will set it to the last saved setting that wasn’t “off”.

And yes you have to long-press the volume knob on the PCM to shut it down. It will not come on when you re-start if you do that.

 

When I Auto X the Cayman I must turn off PCM and HVAC before EVERY run.

 

For my HPDE runs, I have a Post-it note on the steering wheel to remind me of each setting that needs changing.
Radio, HVAC, wing, Sport Plus, PASM

 

If I recall correctly, the HVAC settings are associated with the key FOB and are saved when you lock the door with the key FOB, then are restored when you unlock with the same key FOB. I think that is selectable via one of the vehicle menus. The conditions as to whether they are actually saved/restored always seems a little whacky to me.

 

Why is dealer service so wonderful?

 

I can only guess that Porsche training for the tech stuff in our cars is woefully lacking. I get the impression that their service techs are very competent when it comes to the car mechanicals, but when it comes to PCM, coding, etc., responses across dealers are highly variable. I had a service manager tell me yesterday that "We don't know too much about the PCM and operational stuff. That's usually up to the salesman to explain how everything works and answer your questions about the tech features." But ask the sales rep about coding to change certain features and you get the response, "You'll have to talk to service about that."

 

On my 2016 CS I found that if you hold the fan switch down until it actually reads "OFF," it will stay off. In the beginning I was only holding it long enough to not show any bars thinking that was off. Try that. And the radio works as explained above, push and hold. I read the manual several times and did not find either explained.

 

Tried that in the beginning of this quest. Makes no difference....fan still is on when I re-start.