Does it basically just check to make sure the catalytic Converter is doing it's job?Yup. Every other year till after your vehicle is 4 years old (I believe). It ends when its 20. In Pierce County (south of Seattle) its 15 bucks and you get two trys. If it doesn't pass you can get a waiver for the cycle by showing you had emissions work done by a certified shop. I think it has to be a couple hundred bucks. It's all connected to your registration so if your address is in a area that doesn't require it you don't have to get it. If you do then you can't buy tabs till you pass or have the waiver.
Is there anything I should get checked out before treking out to Seattle? What happens if I fail twice? Is it basically a "smog tax" if it doesn't pass. I pay a fine and then I can drive it?