please help, i got problemos

[scott2461]

hey all,
i was asked to drive a friend's 2003 s60 from l.a. to d.c. and i'm almost there. unfortunately, i've picked up a few problems along the way.

1. Engine service required light on. God knows what this means, I don't expect anybody to have any ideas on this one, so scratch that, forget I even mentioned it.

2. Exhaust system service required. I've replaced entire exhaust systems before, but these were carbuereted vehicles from the 80s. How complicated is the system? What, potentially - worst case scenario, could be wrong here?

3. I've got the rattle. The front right wheel makes noises like it has a loose nut somewhere, especially over potholes/bumps.

4. It's an automatic with 90k miles on it, and it occasionally stalls out or nearly stalls when hard braking or hard turning. My buddy who owns it was a little neglectful about oil changes...

5. The alarm went off today, and now the radio will not turn on. The cd ejected all right, so the power is still there, but no other button gives any response. This fifth problem is of the greatest importance to me since I still have a good 800 miles to drive until I drop it back off with him.

So if anybody has any ideas on any of these problems, I would greatly appreciate it. I've got marginal experience working on cars, though I'm more or less clueless with all this computerization, but if possible, I'd love to kill a few of these problems with a socket set and 10 dollars at advance auto parts, rather than dropping it off and suggesting he drop a grand at the dealer. Thanks again,
scott