ok so driving along, all of a sudden the sound cuts out on the stereo and there is this big error message on the PCM > "cannot communicate with pcm / stero / cd / amp" (or something to that effect).

I shut off car, restarted, everything started working and error went away. What needs fixing?

I have the Bose / Nav, 04 CTT.

 

Your MOST fiber optic network has lost the ring. On 04's I recall a few of these over the years. They have been, plug fell out of componant, hard bend on fibre (1 link down), catastrophic failure of one of the componants (like the amp). The MOST network is 1 loop so it could be anywhere, the dealer can see the fault on PIWIS.

I would check the fiber plug in the back of the unit (orange cables)

 

thanks- sounds reasonable. perhaps it is a loose connection since the ring came back up after restarting the car.

i'm going to be installing a mObridge (rennlist GB price $499!!!) hopefully this weekend so will check all of the fiber plugs. Too bad I can't use my network FLUKE tester on the pcar fiber ring... lol

 

Great idea

 

I had the same issue with my 2004 Cayenne. Only modification to the PCM is an FM Modulator.

Problem fixed itself.