yes, a shop scanned for codes, and yes the scanner was 8000 bucks they said, it will read abs, i dont know the model scanner, it looked like a tablet,, touch screen,, had a plug in inside of car, with module, then wireless to tablet, it also had a module that was inside of bldg. plugged into computer/desktop, all big shop stuff

One of few problems may exist by the sounds of it.
The ABS module is not able to communicate because of a scanner related problem or the ABS module could be defective.
The most advanced specific scanner for these cars is a TechII.
GM dealers have these scanners and technicians trained to use them.
I would recommend that a TechII be utilized at his point.

You could have a bad ABS module, but I keep coming back to you washing the engine just before it happened. I would check for loose or broken wires around the control module, and possibly pull off each of the electric connectors, make sure there is no water in them, and apply some dielectric grease before putting them back on.