Check Engine light Causes??

Wonder what the most common cause for this light to come on?? Emissions
perhaps?? My 2003 Accord has had this problem due to gas cap.. Comments??
TIA

 

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.....