I have a 2005 cayenne s. The PCM had been working fine up until the last few months. Nearly everytime you get into the car now and start it up the PCM comes on however the SAT NAV, AMPLIFIER and PHONE will not work.
A message stating
PHONE, NAVAGATION & AMPLIFIER NOT AVAILABLE.
I spoke to the specialist at my local Porsche dealership about this and he said he would need to get the car onto the diagnostics to identify the fault.
I arranged to bring the car down to him when the fault appeared again.
As i stated this problem occurs nearly everytime you get into