shutdown

Hi I have a 2004 gmc envoy, and I've changed the front and back brakes. and I get a message in the little display window that reads check brake system, and it'll shut my suv completely down. I'll have sit and wait a few minutes to re-start, and pray that I make it home safe. I've also changed the sensor on the front brakes, b/c there's no sensor on back except the transmissions? What could this be that's making my car shut down completely what else needs to be done.

Welcome to AF. A full scan of the ABS will probably show you whats going on here. All 4 wheels have there own ABS sensor also.