I left the key on for several weeks and the battery is dead, recharged the battery , turn key on , nothing happen , is there any reset button on this car ?

Check your battery's voltage to see if it is above 11.89v. When the battery is at 11.89v...it is at 0% state of charge and only the battery's reserve capacity is what can get the car going.

If you drained everything out of the battery...it may not have enough volts NOR reserve capacity to start the car.

Are you getting any interior lights and aux stuff to come on? If so, unlock the OBC and do a TEST #9 and see what the battery voltage is. If it is consistantly between 10.5v-11.8v...you probably don't have enough power to get the car started.

Good luck...and instructions on how to unlock the OBC can be found easily doing a search here...or you can go to www.e38.org (do a page search there to skip over the stuff you don't need)

You can perform a page search by typing [Ctrl+F] (if you're on a PC)...or [Open Apple+F} if you're on a MAC.

Thanks you Qsilver7,

I was able to unlock the OCB ( got to step 19, pushed left button until my added number appears, push right button , it went back to test 1, bumped up tp test 19 then left button it display OFF)
I went to step 9 and it showed 12.5, I then took the key off the cylinder , then proceeded to start the car , still nothing happen , not even a dim on the interior light , help help

Finally, I got it to start, I think it is the combination of 2 bad things, Car battery and key battery were both dead, I used the spare key and it started right off.
Thanks

Finally, I got it to start, I think it is the combination of 2 bad things, Car battery and key battery were both dead, I used the spare key and it started right off.
Thanks

Hmmm.. correct me if I'm wrong, but the key should work regardless of battery power; the spare key has no battery. The starting process is explained in this document:

http://www.e38.org/EWS.pdf

As it shows here,
http://i3.tinypic.com/6h3fd74.jpg

every key (including spares) has this chip, which (as I found out recently) is only attached to the master key with glue, and not any wires. Maybe leaving the key in for weeks somehow damaged the chip? One thing to try is to hold the spare key near the ignition while trying to start it with the other key... it would be really interesting to hear about that experiment. If you decide to try it, let us know! But I'm glad you got it to start! :redspot

I tried with the bad key first , did not work , held the spare key near the ignition , still not working.
Used the spare key to start the car , it started, then I tried the bad key the second time , it started , ( this warning displayed : " Remote battery low " ) By the way , when I said spare key , I meant another real key , not the valet key

I tried with the bad key first , did not work , held the spare key near the ignition , still not working.
Used the spare key to start the car , it started, then I tried the bad key the second time , it started , ( this warning displayed : " Remote battery low " ) By the way , when I said spare key , I meant another real key , not the valet key

Just an FYI...there is a brief window of time where the EWS key identification feature is cancelled right after removing the key and re-inserting it...or as in this case, a key that wasn't working before...so make sure you don't get over confident with that one key that wasn't working previously.

The DME will retain the ISN (individual serial number) that was sent to it by the EWS control module for 10 seconds after the ignition has been shut off.

Very nice Q!!

" don't get over confident with that one key that wasn't working previously. "

Exactly, the bad key did not work the next day.
I got the 2 new batteries, and keep that key as spare now.
Thanks all