I keep getting an error on the display to service rear park sensors. Then the on/off button turns off auto. A bit later the on/off bottom will turn off again by it self . Can't find anything in the owners manual on it and no code shows on code reader, Any ideas?

code reader can only access powertrain codes. the park assist system dtc will have to be read with a full function scan tool.
get the code read and post it here.

the sensors emit a signal that can be picked up with a mechanics stethoscope. have someone put in reverse and you listen for the sound at each sensor. if one doesn't make the ticking sound, it probably bad.