No it did not come on at first. If if did I would have had it scanned to find out what was going on. It just seemed like hard starting occationally and died a couple of time when coming to a stop light. It didn't come on until it started dying while driving and not re-starting right away. When you turn on off the ignition as in trying to start it, the CEL will reset and turn off. The tripped code is still saved in the computer. This crappy sensor is liKe a progressive disease. Just an annoyance at first and you don't knwo what is going on.