My Volvo’s down in the back…

Hello, since I was helped so competently with the last problem, here is the next problem: My V40 (with a large car gas tank in the wheel pit) is down in the back. I always thought that was connected to the tank, but otherwise there is the bike. It shouldn’t make much difference to my understanding. It’s not terribly much, but it bothers me. What’s the matter? The car has already 193,000km on the clock… What amount do I have to plan for a repair and could you do it myself without much effort?