Hyundai Repair: Engine Light, negative battery cable, vapor control

Question
I have a 2002 Santa Fe 6 cyl.Engine light appeared,took to Autozone,was told it is code 455,leak in evaporative system.Is it possible to diagnose without taking it to mechanic?

Answer
You'll probably need a mechanic to properly and thoroughly diagnose this code, but that's not my first recommendation.  

Your evaporative system tests itself by creating a vacuum in the fuel tank and vapor control system.  If your fuel cap is loose or off, it may not be able to create this vacuum and therefore set P0455.  I'd recommend making sure your fuel cap is installed properly (tight and not crossthreaded) and then disconnecting the negative battery cable for five seconds to clear the engine control module (ECM) memory.  

If the lamp and code come back after you've done this, then I'd recommend taking the car to a mechanic for diagnosis.