do you have abs? and by emissions light i assume cel?
if you do not have abs, there is no way for it to signal a light, but you will have problems with two different tire sizes on the same axle..
if you have abs, then if the rolling diameter is enough to cause a speed difference in the abs sensors, that the car cannot correct, then it could trip a light (speculation, i dont have abs on my aveo, and most cars with abs or traction control that do this has a separate brake or traction light).