Check Engine light Causes??

I think that is the single most common cause; evaporative emissions fault (failure of fuel vapor system to create the expected pressure differences). Beyond that the sky's nearly the limit. Many cars, including Hondas, piggyback a whole lot of system fault indicators on it to make it a genuine Malfunction Indicator Light. If the Vehicle Speed Sensor fails completely you will get the light.

It will *not* report the critical things like loss of oil pressure or overheating. Those have dedicated indicators for their functions.

Mike

All cars since 1996 have OBDII systems as mandated by the EPA. They monitor all aspects of the emissions systems and if any are out of specs a code is generated and the check engine light is set. If not fixed some problems will cause other failures such as destroying the catalytic converter. So if you have a check light it is a good idea to have the codes read out and find out the problem. If you live in an area with emissions tests you have to have it fixed.....