Hello,

Not sure why my Cayenne turns 'semi-off' meaning I can only get very low engine power and all electronics go down; with brake force distribution fault code. I have to turn off and then turn it back on. Starts up again no issues. But then re-appears randomly. Has happened 5 times in last 2000 km

I would guess your battery. Seems just about every time funky electrical stuff comes up, it's just in need of a new battery. If that's not it, then I have no idea.

I would guess that before throwing parts at it based on interwebz guesses - you might get a Porsche diagnostics tool of some type or visit a shop that owns one - and see what codes are stored in the modules. There are MANY codes that don't trigger a CEL. Given the severity of your failure mode I'm certain there are codes stored. You do need a PORSCHE specific device to read the codes - a standard OBD-II code reader won't hack it.

BTW - it might be useful to know the year/model of your Cayenne. The guesses people make will be very non-specific if you don't provide that information. You get better answers if you ask better questions (me.)