Hi I drive a 2004 accord 4 cyln , I have noticed that while removing the cap from gas tank ( right after engine is turned off with 1/3 of the tank empty) I hear no "hissing" sound. this means there could be a problem with EVAP but I do not have any MIL on. Has anyone experienced similar situation before? thanks for your feed back.

 

Verify that the check-engine lamp actually works. Look for the bulb-check for 2 seconds when you first turn the key ON.

If the CEL is OK, then you can trust the ECU to know the EVAP system is OK. An actual functional check of that sytem takes something like 8 pages in the shop manual.