My 2003 PT Cruiser Turbo won't pass inspection because the catalyst & evap sensors "not ready"... how can I remedy this?

Did you just buy the car? I don't understand that you've driven it for over 400 miles. If you just bought it, the owner has to get the car smogged before you can register it in your name.

I call it mine - cuz I am planning to buy it, just haven't purchased it yet. But I have done so much research and it seems that the on board computer is the next thing to change out. The car drives and rives great... it's just that both sensors can't be "not ready" at the same time... it's one or the other but not both.

sure they can not be ready at the same time, i had cars that had to be driven well over 1000, miles....do not go changing computers, the best way to make them set is to drive them in the city, the highway prevents it from heating up, as the high speeds cools the cats down, and they need to get to temperature before it will. there is no set in mileage as to when the sensor acknowledges temp.

Try John's suggestion. Just don't buy the car until your issue is resolved. As to the 2 "not ready" indicators can not be on at the same time. My answer is: I've worked with computers for 40+ years. If it's a computer related problem, anything is possible.

for evap to run the car usually needs to be cruising at a steady highway speed. The catalyst monitor being not ready can mean the heater in the o2 never heats up, or other poblems. Jumping to the computer this soon is a little drastic. The evap isnt a "sensor", it's a system. There is a purge valve that may not be working. Or maybe the computer isnt getting power when the car is off to keep the memory. Unless your getting a killer deal I would just find something else.