Auto changing modes or turning off.

Since that switching is controlled in the faceplate (an entire circuit board), first thing would be cleaning the contacts of the faceplate-to-main unit connector with a good contact cleaner (i like Caig DeoxIT products).

I didn’t have exactly this problem, but given your description, the problem i had seems closely related. I did clean my unit’s connector, but it didn’t help on mine. If that connector is not the problem for you, keep reading.

Imagine if there is some conductive or partially conductive material in one or more of the pushbuttons (the actual electrical “tact” switches) in the faceplate assembly. Such material might be a dust or powder or something which could change in conductivity with vibrations/road jolts. If true, as far as the button matrix processor is concerned, it would be like a user actually pushing a button or rotating the rotary control.

On mine, there seems to have been enough contamination that mine acted like one or more buttons were continually jammed down. It locked up, doing what it wanted (mostly acting dead). Another poster here discovered that pressing the CD Eject key on his unit turned it on (from having acted dead), but he had to hold that button down to adjust the volume. On mine, one press of that button re-activated the CDX-GT565UP, and everything has worked normally since. This suggests to me that these faceplate switches are prone to some form of contamination, or maybe even internal breakdown. I go into more detail in my answer to the Eject button question.

Yours may be a variant whereby the conductivity is momentary, but not continuous, so it acts like a regular button press rather than a press and hold and hold and hold. Conductive push switches may not be the problem yours has, but IMO it’s worth checking.