Traction Control

Ok so I purchased this 2008 Mazda 3 2.0L. I noticed the TCS light was flickering off and on. I later realized that 3 of the tires were 205/50/17 and the fourth(front) was 225/45/17. I knew this was the problem so I immediately put the odd tire on the back. Light still on and front end is a little squirrely. I tried to reset it by disconnecting positive battery cable for bout ten minutes. Didn't help. Is there a way to reset it? Will odd tire on back still affect the TCS? Anyone have any advice to get me in the right direction? I'm going to replace the odd tire asap.