I had the same problem. I lent the game to someone who returned it a year later - minus the wheel.
I can't remember how we figured this out, and it's a far from ideal solution, but we somehow remembered two codes and their corresponding entries. If you keep re-selecting an option until either B5A5 comes up, its correct entry code is 231.
Similarly if 0000 comes up, its code is 000.
That's what we used to do anyway, although as I say, it's far from ideal as it involves a lot of re-selecting and aborting because, as I'm sure you're aware, if you enter the wrong code three times the game refuses any more attempts and you have to reboot.
Still, might be worth a shot until you get a wheel sorted out. It's too good a game to consign to the back shelf.
