Ok, my car threw a P0456: Evaporative Emission System Leak Detected (Very Small leak) the other day.

No big deal, but I am curious as to HOW the ECU makes that claim? I.e. what sensor is responsible for this, and what conditions have to be met in order to generate a P0456?

FYI, I run a full v-band flanged exhaust >> (DP][cat][tailpipe][muffler)

l8r)

 

Could be because you gas cap was not on tight...

 

^ yup. Most likely loose gas cap.

 

Ok, so which sensor(s) report the conditions necessary to trigger this CEL?

l8r)

 

good question.

I'm sure there is an electric close circuit sensor that's there when you close the gas cap.

I think there is one built for the oil caps.

So if the part of the metal on the gas cap doesn't line up with the metal sensor on the car, it'll give you that signal.

Of course, I'm assuming, since this is usually the most practical way to detect things via logistics.