[Taka2005]

I'm a bit confused about these "codes"...

Whenever there is any sort of engine or emissions malfunction, will there always be a Check Engine light along with a "code"? Is it possible to get the Check Engine indicator without a corresponding code? Are these codes displayed on the DIC or can they only be read by scan tools?

 

[Rob in CT]

Anytime your engine light comes on, there will be a code stored. If you have a drivability problem, but no check engine light, there usually isn't a code.

 

[fergyflyer]

There also will be codes with no check engine light. I think these are minor codes that only happen for short times periods. An example would be a misfire that only happens once would throw a code but not trip the check engine light.