my traction control/service stability control light keeps coming on on 2005 Buick Terraza

Lately I have been driving down the road and my service stability control light has came on and at the same time it seems like the brake atomaticlly comes on and the van pulls to the left. Any ideas?

Asked by for the 2005 Buick Terraza
have abs codes scanned and post so we can adv
where do I get abs codes?
with a special scanner