Wackler at ABS / ASR ??

Hi, back in the round!

Our little one (2.8 Bj. 1097) once again has a small Macke.
As soon as I start it and hit the steering wheel, the ABS / ASR warning lights are on (and ABS and ASR are in fact without function). I turn off the car and start the lights again and everything will work again.

It happens every now and then, even if I park slowly with the steering and drive over a lowered curb PING are the lamps on.

I drive around normally all the time, nothing happens, whether pothole or anything else the lamps don't work.

Could it be that there is a problem there due to moisture (we had water in the footrooms through the stopped processes behind the center console)? There is a lot of electrics/electronics under the thick wooden plate in the passenger footroom.

Or just clean the sensor(s) (where can I find them?)

I say thank you again for your answers!!

Greetings from the South of the Republic where autumn has now moved in

Jörg