I just use a cheap 2button obd2 scanner. Does its job well.
There are more expensive ones that tell u some other things that could be wrong with the car, like with the srs...

I had the same type of problem not too long ago and i got the code for my o2 sensor. Replaced both of them and its running strong now.

Your cel bulb might be out like mine is. I just scan mine very frequently for anything new that might come up. I would scan it weather ur light is on or not just in case.

 

Thanks to all for advice.
Much appreciated