My car threw a check engine light today. Other than the light there is no symptoms at all that would indicate a problem.

I know this is very vague, but does anyone have an idea. What would most commonly trip the CEL with no drivability symptoms.

 

Check your lights? Maybe a dead light setting it off? A local auto part store such as autozone will check it for free.

 

Could be something so simple as a slipping serp belt. Get it checked for code/s.

 

+1 asking any of us to predict why your CEL is on would require a crystal ball. Unfortunately, I dropped mine last night in a drunken stupor and it's not working right.
So, you're at the mercy of someone with a scan tool.

 

My most common reason for getting a SES (or CEL) light is emissions related - either an O2 sensor going bad, or even something as simple as not having the gas cap screwed on all the way.

Either way, as the others have stated, any auto parts store should have a basic code reader to get the code for you.

 

Ok guys thanks. Ill get it hooked up to a scan tool.

 

i had this recently and found out it was a bad gas cap (a loose gas cap can trigger two lights, either the check gas cap light or a CEL). my cap was about 10 years old so just rpelaced with an OEM one, i had to reset the CEL though since those will not reset on their own.

in the end i bought a $20 bluetooth OBD2 adapter and an app on my android phone to reset the CEL. way cheaper then going to the dealer to reset the CEL.

the adapter is useful to have since it will read OBD2 codes for other errors

 

I had one when I first got my MINI (preowned), I believe it was "leak diagnostic pump", which I believe is part of the fuel system but I don't even know what it does. Diagnoses leaks I guess. ?

In my opinion, you should invest in an OBD2 device.

I have a Bluetooth one and I use it with my Android phone with an app called "Torque", which can actually display a lot of useful info about your car in real time (e.g. temperature). You can use it to reset your light as well, but it'll just come back after a couple of trips.

 

This was my issue and is a very common problem with all cars.

Obama a couple of years ago pulled all of the zinc out of oil and fuel that goes in cars. The zinc is a lub for older cars that don't have roller cams like all modern cars do. The reason that I mention this is that zinc is the one of the top reasons catalytic converters and O2 sensors go bad.