My check engine light came on and I got it to read on an OBD II and it came back as a "PO455-EVAP Emission Control System Leak (Large)." Car-2002 Elantra seems to be running fine at this time. However, there is an audible "vacuum leak" that the parts guy pointed out when the hood was up coming from the rear of the engine area. Any hints or solutions would be appreciated. THANKS.

 

The vacuum leak under hood is probably pcv hose.They go south alot on older vehicles.Po455 is basically a large leak in the evap system.Some say its a gas cap and roll it out the door.In order to have this leak properly diagnosed you have to connect a low system pressure tester to the evap system and test to see if pressure drops.These are factory tests.You can have a quick test done at your local dealer for a evap leak using the high scan pro.It is not always accurate as the low system pressure test.If you clear the code and it re-occurs you need to have this addressed as for most states wont pass a state inspection without vehicle passing readiness tests in pcm.