I took my X to the dealership in Plano, TX this morning and they replaced the battery under warranty. The Job description says, "CHECKED BATTERY. BATTERY HAS BAD CELL. CHECKED CHARGING SYSTEM. CHARGING SYSTEM is GOOD. REPLACED BATTERY. 80N1G-G35K1". I'm hoping that is the issue and hopefully it won't die on my far away from help. :)

I am having the same problem with my 01 X5 4.4. I tend to believe this problem is fuel related. Does anyone have the silver bullet to fix this problem? Has anyone changed the fuel filter filter/pump to fix?

Yes I replaced the fuel filter and everything else. Did it help, maybe, but if in doubt do it anyway. I just found out my problem wasn't fuel related since everything checked out fine (New filter and 50psi coming from the pump). My local mechnic and the bmw dealer couldn't find the problem but my third guy did, an air mass sensor was bad.

Hey dawsenk, check out this thread

http://www.xoutpost.com/x5-e53-forum/...-starting.html

It's 12 pages but worth the read, a lot of X owners seem to have this problem and the common fix seems to be the iginition switch.

toohotdoc. try different key and let see. sometimes the key is bad.

i have tried using a different key, even the valet key but that was a no go. I recently jump started the car when this happened last time and it worked, i am convinced that it is a battery issue. I will replace my battery my tomorrow and does anyone know what is the best battery to buy for a X5?

i got the diehard at sear for 3 years now and it still good.

finally took the truck in after i couldnt get it started, and had to tow it in. Now, a week later i am told that it was a relay that was faulty and that was the reason for the mis-starting. So my starting issue was due to a relay and not battery or fuel filter/pump which i thought would be the cause.

Hello, I'm having the same starting problem. Just changed the battery but the starting pain is still there. Do you happen to know which relay was replaced? Thanks.

Ahhh, very good weed hopper (in the most oriental sounding voice I can come up with). I just came back after a long time away. As I was reading this thread I wondered if anyone would remember. After that thread my "01" has started every time. 145K and counting.