will a car fail an emission test if the check engine light is on

Yours will. If the vehicle is 8 to 11 years old, only a check engine light test will be performed. If it is 7 years old or newer, no test is required. Older than 11 years old, the old style dynomometer/treadmill test will be performed.

One thought - my check engine comes on from time to time and goes off by itself within 48 hours - Usually when I was cheap and put in regular gas - never comes on with premium and is always a secondary oxygen sensor. If light is permanently on check with autozone - they usually will do a code check I was told. My wife's Saturn check engine light comes on from time to time - disconnect battery and wait ten minute reconnect and good for another year - LOL