Transmission failsafe and more problems

[Ted M]

Our 2005 X5 4.4 did the transmission failsafe thing a couple days ago, we turned everything off and restarted, had no problems until last night, where one key will not start the car (won't turn over and actually keeps doing it when I let go of key...) and the other key starts the car, but its extremely rough and the temp gauge is all the way hot immediately. Any ideas on this would be much appreciated!

[faranks]

Originally Posted by Ted M

where one key will not start the car (won't turn over and actually keeps doing it when I let go of key...)

do you mean the X continues to crank but will not start? You may not know that you only have to push the key forward to start position to start, it will continue to crank even if you let go and key rolls back.

anyhow, many on this forum have had this same problem, including myself. I personally believe it is due to the Vehicle anti-theft system that reads a code in the key, being unreliable. I tore my key cylinder apart, scoured the molex plug that carries all the wires away from the column, to no resolve. I had the problem for a while, then it went away. No explanation.

The other symptoms you describe would worry me more. I don't know how long you've had the car, but the X is notorious for all sorts of gremlins.
The trans failsafe is what may be trouble. I just rebuilt my X's transmission, but was having more symptoms than just a dash message.
Maybe you could give some more info.

[killcrap]

A situation occurs on 2004-2006 X5 4.4i engines where the PT-CAN does not recieve the correct voltage, this causes long cranking, and the temp gauge goes to the red.

Interrogating the fault memory of the vehicle will show a kl15 fault in the instrument cluster. Replacing the ignition switch will remedy this fault.

[PUREVIL]

I've experienced the "continues to crank but won't start" problem. Turned out to NOT be a problem. I simply needed to remove a pile of keys from my ring. The extra weight must have been the issue because that cleared it up for good.