Having recently suffered the now all to familiar coolant leak issue, and paid for the repair myself - as Porsche wouldn't pay a penny - I came back from a weeks holiday to another problem with my 2006 Cayenne S which has only done approx 40,000 miles;
After about 15 minutes in the car I noticed the screen on the PCM would flicker for literally a split second probably every minute, when doing this it was literally a blink and you'll miss it type of thing where the screen looked exactly the same before and after the flickering but after it had done this a few times I turned the screen off and then back on again to see if this would fix it but it didn't. I then turned the PCM off for a minute and turned it back on again and it was fine and had no further issues with it that day
The next day when driving back from work I turned the PCM on and the Porsche logo with the white background (start up screen) appeared for a lot longer than normal (probably about 20 seconds), after this it went on to function normally where I could control the radio, CD etc.
However, the next day I couldn't switch the PCM on at all, and have been having this problem now for 2 days. Yesterday the PCM came on by itself without me pressing any of the related buttons but since then I haven't been able to switch it on at all.
From reading other posts about people having problems with their PCM's I've seen some have had issues with the screen and when they've pressed it this seems to have solved the issue, but I can't even get it to switch on. I've tested the battery and it's fine so it can't be that.
Can anyone PLEASE help with this!! It seems to be one issue after another with this car.
Thanks in advance