I've basically bought my last two Porsches on the recommendation of the service manager at my local Porsche dealership. I trust him, and he knows I will be the first one arguing with him is the car is a problem car. So far so good here ...

I asked him about the key fob / entry-drive problem and he said this:

"As far as the Panamera I would need to check it and see what might need to be done. There is no single one fix for that. Radio interference does come into play but then again we have seen a few issue with low key batteries or keys themselves. There are other things also but I couldn't say what the fix is without doing some trouble shooting."

So apparently, there are a myriad of things that could be causing this issue.

 

It's good to know someone like that - I'm fortune also. In troubleshooting the dealership has replace the rear controller and the front controller, the rear antenna, both keys, software versions, moved the antenna closer to the driver, and rerouted the rear antenna wire away from interference. I'm not sure what else is possible. The last change (moving the antenna) seemed to have the most positive impact for about a month. No longer. Honestly the way it acts (sometimes working - sometimes not in the same location with no change - sometimes no cell phone) I wonder if it's a software bug.

 

For me, replaced batteries on key fobs, even deleted and re-added key fobs to the car, they also did checks.

I have to be no more than 5ft from the rear of the car or infront of it for the door to open. if I'm standing right beside car, I would have to put the key fob in front of windsheild or rear windshield. My lexus I can open or alarm it from 30-40 ft. More if I put the key fob on my chin.