ACC Panamera 970

I have an 2009 Panamera 4s with Adaptive Cruise control.

Which is Lovely for a car that is 17y Old.

But i noticed for a while now that the first 20 min of my trop everything is fine.
but then it starts to cut out every 10-40 mins with a blue message „ACC Unavailable“

(No matter the driving conditions)

It also cuts out when not using it.

And after 2-5 mins its back on.

Could this be an old battery issue?
For example a voltage drop which may be caused by the air compressor or so?

I checked it out with PIWIS 3, The ACC module Error code Only tells me that the sensor is „Blind“

Any suggestion is appreciated.