$10,000 might be a bargain for a kidney transplant, but that doesn't mean I would want to pay it, or to have to go through the procedure, if I could avoid it and stay healthy.:bustingup
Seriously though, thanks for all the comments. I do realize it may ultimately come down to having to perform such tests to find a solution.

It is interesting position and you cam enlighten us how do you plan to fix [any] of your car[s] in the future ;)
In Imalabil's case the car is under extended warranty and the shop may easily spend a grand or more in parts. Would you follow this ?

Want to wait until P0442 shows again, and take it in with the SES light illuminated. If not, I'll have them just fix the AC.
Filled it with gas tonight and no smell.
BTW, did I mention my G8 does the same thing? Mostly it sets P0442 when it gets cool quickly. They replaced the gas cap which helped a little, but she's out of warranty now.

OK. My CEL stays on continuously, though.

Light doesnt matter...even if the light goes on then off, the CODE is still trapped in the DME

The issue I had was with a code P0456 - EVAP System - Very Small Leak Detected, but to me it seems the same as yours.

Things I would notice while experiencing the issue:
- smell of gas inside the car
- smell of gas outside of the car, about the back of it (especially on hot days and after tank got to half +/- a 1/4 tank)

I was able to fix it.
My fix included:
- replacing the gas cap (I don't think it was the problem)
- replacing the seal, clamp, top retaining "C" assambly clamp on the fuel tank pump under the passenger rear seat (I don't think this was a problem)
- pulling fuel pump up and after disconnecting the connector noticing one of the pins had melted plastic around it. I filled the hole with JB Weld and connected the electrical connector to hold the assembly together until jb weld dried. Obviouse repair would be to replace the fuel pump. (this was the apparent problem)

All in all I understand that the original firmware in the x5 sends too much current to the fuel pump and it keeps connector hot, melting plastic around it. I had new firmware loaded a year after I got the x5 (car was five years old at that time), but the damage was already done.

I did the repair about two months ago, all is good now.

What caused that connector to heat up is not too much current, it's either a slightly loose connection, or a little bit of corrosion. The current bridges the poor connection, in return, making little tinny sparks, and causing heat. Certainly not the best thing around the fuel pump. If the problem reoccurs, I would clean the contacts and pins very carefully on that connector, and use some good contact cleaner on it. I might want to use some dielectric grease on the connectors as well.

sounds about right....

All good stuff. I will be checking my electrical connections. A poor connection equals resistance. Current lost to resistance is dissipated primarily as heat. Too much heat in one place equals trouble.

It would be great to follow this through to a fix. I am having the same code P0442 and is keeping the CEL on. The 2009 X5 3.0 is out of warranty and is sitting at 56K miles. It runs very well with no smells or hesitation. I purchased the BMWhat ap and reset the CEL and the X5 would run with no errors for several days. It starts with the check gas cap error and then later puts up the CEL a couple of days later.
I purchased a new gas cap and the problem came back quickly.
I then purchased a DMTL pump and did the replacement procedure posted from Gregg3gs.
Visually inspected the hoses and checked the connections at the wheel well side.
Looking for the next step or taking it to the dealer. MD has the worthless emissions inspection and will need to get this resolved so I can pass inspection and stop paying penalties.