2004 impala 3.4l\r\none day the park bra...

2004 impala 3.4l one day the park brake idiot light came on, which is on the left side dash. and also the low brake fluid warning came on and stays on the info board on the right side dash.
I chked and topped the master, no fluid really needed. the fluid doesnt look that great. I was considering bleeding/changeing with fresh fluid. also a friend plugged in his t-code reader and came up with something like overspeed indicator rt side rear wheel?
any ideas? I am about to pull all four wheels and do a visual.
however i'm hopeing this might sound familier to somebody. thanks,