The flex cables to the front sensors in the hubs can break or could be bad connections. You can jack up the wheels and check the outputs with a meter to see if they are working. I think the rear sensor on your car is in the diff but can probably be tested the same way.

I had the same problem and replugging the front sensor cables seemed to sort it.

 

agree with what the guys are saying. see if your ebrake is all the way down. also check the rear brakes for any sign of fluid leakage. u can reset the brake light by pushing on the brakes really hard.