So after a few years of looking into buying an XC90 and I finally made the leap and bought an '04 with 120k miles. I do have a few questions/concerns and I would love any answers or advice anyone could give me.

1) the door to the fuel tank won't stay closed and it's driving me insane! It seems like it is locking itself but not with the fuel door shut so then it won't close at all without hitting the unlock button for the fuel door. Not sure if it's something I'm doing or if it is something that could be a simple fix. Even if someone could tell me when or how it locks itself when the door is working properly.

2) I was playing around with many of the features inside the car and I discovered the integrated booster seat. It was difficult to get it up and I'm almost positive that it is not properly locked in the position where the booster seat can be used. Then I went to move the seat back to the original position and it was stuck in this in-between position where it is not fully the booster seat but won't go back to the regular seat and I'm not sure how to fix it.

3) The navigation system reads an error message that the dvd slot is open and needs to be closed but I don't know how or what to do there appears to be nothing to close?!

4) the dealership only had the spare key, not the one with the remote. What is the usual cost for replacement and does it have to be done at a Volvo dealership or can a regular mechanic do it? Is it something that can be diy?

I would really appreciate any information!! Thanks