2008 2.0 Mazda 3 traction control

I just purchased this 08 mazda 3 and immediately noticed the track sensor light had came on and it was pulling to the right pretty good but figured an alignment who fix it. Started looking at tire size cause it would need some soon. That's when I realized three tires were 205/50/17 and the front driver side was a 225/45/17. Figured this was the source of the problem. Hooked scan tool to it and came back w no problems. Any help would be very helpful. Thanks.

I also want to add that I put the larger tire on the rear hoping it would help but it didn't. It was pulling to the right really bad until I moved large tire to rear, now it pulling to the left. The traction sensor light is on but it's not throwing any codes. Is there any way I can reset the sensor? I'm not sure what direction to go.

Having one different sized tire is going to cause you problems. If you had 2 tires of that size and 2 of the other size (one size on the front wheels, the other size in the back) it wouldn't be such an issue, hell it may even improve the handling.
Also, having that one odd tire could throw your alignment off if you leave it on there too long. My advice: Ditch the odd tire and get one that matches the other 3. Also have your alignment checked to make sure it's not out of whack already.

I don't know how long the odd tire has been on car. I've only had the car a week. Do you think that odd tire could mess up the traction sensor? Or speed sensor? I'm hoping that replacing odd tire followed with alignment will fix it.