Will my car pass emissions if the check engine light is on?
No. Your vehicle will not pass the Illinois State emissions test if the light is on. This light is a signal that there is an issue and needs to be professionally scanned and diagnosed even though you think your vehicle is operating OK. Save yourself a lot of time and hassle and see your local mechanic for the professional diagnosis as opposed to your local parts store, which only has a code reader not an actual scanner to diagnosis the problem correctly. Don't be penny smart and dollar foolish, as the quick fix your local parts store may try to sell you, will have you back in line at the emissions test facility, again and again with the roll of the dice am I to pass today...?