Unusual key problem 2001 X5 3.0

[2001 X5]

So went to start our X5 Friday morning only to find it won't crank. Dropped key on sidewalk on way to car. Ordered a new key/fob and valet key. Car starts fine with new keys..now comes the oddity. Old key will start vehicle if you use new key first then the old one AND not remove old key from ignition. Starts every time with the old key till you remove it. SO....what's up here, apparently chip in old key is still good.....??????????????

[upallnight]

Originally Posted by 2001 X5

So went to start our X5 Friday morning only to find it won't crank. Dropped key on sidewalk on way to car. Ordered a new key/fob and valet key. Car starts fine with new keys..now comes the oddity. Old key will start vehicle if you use new key first then the old one AND not remove old key from ignition. Starts every time with the old key till you remove it. SO....what's up here, apparently chip in old key is still good.....??????????????

Nope, chip in old key is bad. Starts the X with new key, turn off engine and remove new key, wait 10 minutes to restart with old key. Does the engine still start?

[white46]

After successful start with good key, EWS is disabled for about 10min after you shut the car off.
That's why bad key worked.
Do what upallnight suggested. After 10min or so, bad key won't work.

[2001 X5]

We tried as you suggested, didn't have to wait 10 mins, about 30 seconds and tried the old key again. Vehicle would not crank. I was so hoping it would work.

[Qsilver7]

You might be able to revive your old remote key.

You say you dropped it...and since it has not been able to start the engine. Since EWS chip is soldered to the key's internal IC board...perhaps a solder joint cracked.

If opening the key & resoldering is not in your wheelhouse...people like Scott (https://www.bmwgm5.com/) does this kind of work.

Did this key still have FZV/DWA capability (remote lock/unlock & arm/disarm) prior to programming the new replacement keys?

[2001 X5]

So update on key..apparently my local BMW dealer couldn't get the old key to work either. Got my new key fob programmed and will be going next couple of weeks to order another key so I'll have 2.

[Qsilver7]

Originally Posted by 2001 X5

So update on key..apparently my local BMW dealer couldn't get the old key to work either. Got my new key fob programmed and will be going next couple of weeks to order another key so I'll have 2.

Remember...you will need to have BOTH remote keys with you when you program the new key. Any remote key NOT reinitialized during the same session will NOT communicate with the GM...and will not lock/unlock & arm/disarm the car using the remote buttons.

Each programming session assigns a specific key code and new rolling code table to the keys...so any remote key NOT present will not have the update...thus will not work remotely.

Here's the programming instructions just in case you need them...plus some tips that some fail to follow...thus fail to initialize their remotes:

• KL R = ignition position 1 (1st click after the OFF position...not position 2 or with engine running)
• All doors must be closed
• All doors must be unlocked
• Only insert the 1st key into the ignition...after STEP 6...start programming the 2nd remote on STEP 3 where you start pressing the buttons

[Thaniel]

Originally Posted by 2001 X5

So went to start our X5 Friday morning only to find it won't crank. Dropped key on sidewalk on way to car. Ordered a new key/fob and valet key. Car starts fine with new keys..now comes the oddity. Old key will start vehicle if you use new key first then the old one AND not remove old key from ignition. Starts every time with the old key till you remove it. SO....what's up here, apparently chip in old key is still good.....??????????????

The car does not re check the transponder 30 seconds after it has been shut off. If it stalls in the street you don't what the security system saying there is a problem and not letting it restart. So if you are starting it with your new key and then switching to the other it is not validating the transponder. You could do this with a key not programmed at all. But dropping your key shouldn't hurt the transponder. Perhaps you dislodged something inside that is COVERING the transponder. Break it open and have a look if it truly isn't working.

I make my own keys so I have a bit of an idea of what is going on :-)