E53 key programming - strange problem
 

I had only one key for my X5 so purchased a blank , had it cut , purchased another working BMW key and swapped the innards.
Programmed it - 'hold UNLOCK and press LOCK key 3 times ' repeat with new key etc .
I now have a spare key that will unlock and lock the doors either manually or remotely , it will turn on the ignition but then the immobiliser will not let me crank the engine !
However if I start the engine with the original key , turn it off and insert the new key it will let me start the engine as often as I want until I open and close the door and then it won't turn the engine over again !
Not a lot of good as a spare key if I need the original to make it work LOL.

Anyone any ideas ?

You need to go to the dealer and have them order you a replacement key that is specifically coded for your vehicle. Take your title with you, along with proper identification. It should take a couple days for the key to be sent to the dealer. As you discovered, you cannot do this yourself with the parts from a remote that was not originally meant for your vehicle.

:iagree:Simple to program it to open/close the doors but it needs to be programed to speak to your ECU. Your only option is to buy a new key from the dealer which will come already coded to your car. Mine was about £100 all in and only takes 24 hours from order to driving away with your new key.

This thread happens every time someone buys a blank key and has it cut... never works. The key has to be ordered by VIN, and there really is no way to make key from blank work...

Decided it is the perfect key to give to my wife - she can open the X5 but not drive it !
She has her own E46 anyway !

Maybe the perfect key to stick in a box hidden under the X5 in case you lock your keys in it at some point... especially so since it can't start it.

That's a good idea !

Notice you live in New Orleans - been there once or twice - a friend of mine lives in Slidell just the other side of 5 mile bridge on Interstate 12 .

Ok,

here's a bit of a strange one..

I have the 01...

my ORIGINAL key just went from working fine, to doing exactly that....

why??

Because it lost the coding between ECU and key?? Not so strange, it happens quite a bit with electronics like this!! I recall the Range Rover used to do this a LOT and cause huge problems for owners who were immobilised due to the complcated way of getting it going again. This is likely a dealer recode in your case.

Just called my local dealer (whom I will NOT name, for their own protection - they're REALLY an excellent group, and offer outstanding service).

Anyway, the service dept person (young gal) tries to help me..

me: "Hi, I'm calling about my '01 X5, having trouble with the key"

her: "I'll be happy to help you"

me: "my key will lock/unlock the doors fine; it won't start the engine"

her: "maybe you need to replace the battery"

me: "already did that - -but remember, it opens/closes doors, just won't start the engine"

Her: "oh... the battery is just weak. get a fresh battery."

me :dunno: "really??"

her: "yes, it is just a little weak.. It takes a stronger battery to power the starter motor than to just unlock the doors. The engine is a lot bigger than the doors."

me: :yikes: "Are you blonde by any chance?"

Anyway, I chatted with one of their mechanics who happened to know the system pretty well.

According to him, there are two completely separate systems in the key. One is the door lock/unlock transponder. It has a large battery (which can be replaced, but he claims isn't recharged). The second is the engine lockout/security system.

ONLY the engine lockout system is charged in this process. EVEN IF your key were left sitting for a time you could stick it in the ignition, let it sit 30-40 seconds, and it would have recharged enough that the chip would fire up the engine.

I kind of disagree with the theory that the remote door lock/unlock circuit isn't charged, because I've seen it go from NOT working to working on one of my keys, after having driven around the mountains for a few hours with the key in ignition... but maybe it was just recharged by the fresh mountain air, and not the electricity? :dunno:

At any rate, i'm going to open up the unit again and see if I can find something cracked.. perhaps I dropped the key and cracked something?

I do board-level repairs all the time, so will magnify it and check out...

A quick followup on my issue..

well it would seem that a couple too many drops of my key cracked something in the remote.

I have some good solder gear at work, so I reworked the whole PCB in the key, and it's now working like a top..

I have replaced the battery in several of these remotes, so doing work on them is pretty straightforward now..

FWIW, if anybody has a remote with a dead battery, i'll be happy to put a new battery in cheap for you.. SIGNIFICANTLY cheaper than buying a new key (I was quoted $165 for a key from the dealer ):yikes::yikes:

I'm going thru the same process before I throw away $170 for a new "useless" key that won't start the engine. I don't think there are 2 separate circuits and the large battery will never get charged if there is not physical path between the metal part of the key and the PCB. The circuitry is isolated from the outside world. I don't see any "imbeded" chip in any part of the key. I checked for transmission of signals off the air, nothing, just when I press one of the bottoms (luck/unluck/back door). So I still wondering if that will fix my problem.

I believe you're wrong here.. there is no circuit between the rod of the key and the PCB. I've had many of these keys apart numerous times (I"m now doing battery replacement for folks and a local dealership).

The ignition assembly has an electromagnet which fires whenever the key is in and ignition set to 'run'. IN the key is a small coil/magnet assembly which in turns charges the circuit for the security assembly. This in turn fires back an electronic code to the engine. That's the extent of my knowledge on this.

There are two or three embedded circuit chips on the PCB, and any one of them could contain a bit of a signal code, enough to do the job. i don't have one handy or I'd show you (i'm at home tonight, and have my own keys closed up again). But i"m certain that at least in this instance, the information is accurate -- it does have a signal bit which is charged by the ignition and which in turn throws out a signal to the starter security circuit.

Another method to prove this is the fact that for a year after my batteries died (Before I got the nuts to figure out how to open these things), I was able to use both my own key and my wife's key to run the car, even though the battery was so dead it wouldn't open the doors. In addition, you could stick it in and it'd start, but even when running the car, the battery was too dead to lock/unlock/etc....

hope that clarifies things....

Quote."..I believe you're wrong here.. there is no circuit between the rod of the key and the PCB..." I'm just saying the same. How could any battery in the PCB be charged, or anything in between if there is not physical link?
My concern is the starting issue, not the lucking/unlucking since it is working, If you take the PCB out of the assembly(store it 5 miles away) will the core/metal still crank the starter? As far as I can observe there is not imbeded chip in the core...I still can not start the engine.

The battery in the key is recharged wirelessly... a coil in the black round part around the key hole charges up and releases causing a charge to build in a coil in the key, which charges the battery. Think of it as a small, low power version of an ignition coil. There is no physical link from the charging input to the voltage output.

And on a fully discharged BMW key it takes 48-72 hours straight to bring it back to full charge.

:iagree: Sorry if I wasn't more clear in this.. If you ever take a key apart, this coil assembly will be very obvious. It's a small rod assembly wrapped in copper wire. It produces the charge for the ignition circuit.

No, the unit will NOT start the car without the PCB. That's the nature of the security aspect. The key rod itself will only turn the ingition assembly, but the internal relays will not pass power to the starter motor unless the unlock code is produced by the security chip in the key fob.

old thread but it didn't seem to be resolved that yes QUITE in-fact there are two electronic systems in the key fob; one for the remote functions and one for the immobilizer.

The immobilizer doesn't use battery, probably similar to RFID or uses a crystal transmitter system of some type to report back a unique identifier code that must match the one in the car.

i've used my key with no battery, it will start the car. I've also tried to start the car when the key fob fell apart and it won't start, the guts are quite required.

my dad's buick would start if the key was within about 6" of the ignition (his lock cylinder self-destructed and i removed all the pins; you could turn the lock with a screw driver, but it wouldn't start without the key near the ignition, but on the seat under the wheel was close enough)

like wedge described; my key was the same; too many drops broke some solder joints loose; it only worked when i squeezed 'just right'. after re-flowing a handful of the solder pin and re-attaching the main little capacitor in the dead center at the bottom the key snapped right back to life.

Lasted a year and then wigged out; re-soldered and back-to-life however the rechargeable battery is shot so i have a non-rechargeable in there while getting the new one ordered.

I'm glad someone "corrected" the mis-information in this old thread! :thumbup:

The statement about it being impossible to use an aftermarket key is also wrong. You can buy an aftermarket key, get it cut to fit the lock, programme the car to allow it to open an close doors etc. (easy - no coding required) and also code the car to accept the key in the ignition (to start the car). This last step requires coding and like programming the remote unlock it requires you to have ALL with you when you do this programming, as all key data in the car is wiped when doing this task.

I've done this on other euro cars - its a mission but it can be done.;)

Hi guys.
I bought a spare remote fob key (an old e39 to program and use just the remote portion) and when I programmed it perfectly last night, now one of my 2 actual e53 O.E. keys stopped remote working but starts car perfectly...

as far as I know this is the first extra key I have programmed to the x5 so it should not have "kicked" another off the EWS...
anyone heard of their key stopped working remotely right after programming another key?

What your described is exactly how it is designed to work. You cannot "add on a key" you reprogram all keys at once. Any time you need to replace a key you need every key at the same time and the car forgets any old keys and learns them all fresh.

Re do what you did with all keys and you'll have them all working.

If the remote dies on an original key you can swap the guts from the spare eBay key if the 8pin chip with the imobilizer is moved over and get a replacement key that remotes and starts the car. You can even get a blank cut if needed.

sensational.
thank you!!! Will re-program ALL at same time tonight.

The 2nd and 3rd extremely easy to add on. I made the same goof when I got my second key

all fixed. super glad. cheers again

Sent from my Nexus 9 using Tapatalk

The reason you need all of your remote keys during a programming session is...this procedure initiates communication with the GM (the control module for FZV/DWA...central locking & anti-theft alarm siren system)...when a key is initialized...the GM assigns a key code & new rolling code table....any remote key not programmed during this session will not have the new info...so the GM will not recognize it for lock/unlock & arm/disarm of the vehicle over the RF frequency the key is sending the data over (315MHz in USA/Canada...433MHz in Europe/Austrailia/other markets).


I'm glad, too that the info about the remote keys was corrected. Yes indeed, there are multiple systems in the remote keys. It contains EWS (self powering) transponder, FZV (central locking) & DWA (anti-theft alarm siren system) which both use the battery inside the key to power its transmission.

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