Coding a new transponder key

[Vin Man]

I purchased a key fob blank and had it cut today. Now I need to get it to start the car and have the key fob lock/unlock the doors.

I've seen a few procedures online regarding programming the fob - along the lines of holding down one button, pressing another 3 times, etc.

But how would I program the car to recognize the key and actully start the car? Do I use NCExpert or Dummy or some other software?

[Our03z4]

You'll need a coding machine and computer to do it, these use transponders. Not so simple.

[Vin Man]

Originally Posted by Our03z4

You'll need a coding machine and computer to do it, these use transponders. Not so simple.

Coding machine is something that attaches to the computer? Cheaper to bring it to dealership?

[elerner61]

Just to confirm, you do not currently have a working key/fob.

[Vin Man]

Originally Posted by elerner61

Just to confirm, you do not currently have a working key/fob.

I have one working key/fob, yes.

I have a second key/fob that has been cut, but not programmed to start the car. It will turn in the ignition, but car does not start.

[elerner61]

Here's an older post from the euro Z4 community that has a procedure, then another link that has much more detailed steps for the same procedure.

https://z4-forum.com/forum/viewtopic.php?t=33506

https://www.pacificbmw.com/manufactu...MW%20key%20fob!

[Vin Man]

Thank you. These directions are for programming the key fob - the lock, unlock and trunk release buttons. The fob on my second key works as I followed these instructions originally. However, the key still does not start the car.

I believe there is a transponder in the key. The ECU needs to know what the transponder key number is so that the computer will allow the car to start with the second key.

How can I program the ECU to accept the new key when I don't know what the transponder code is? I was hoping there was a way I could connect my computer to the OBD port, but the key in the ignition and tell the computer to add the key.

[Our03z4]

This explains about the programmer you need.

[elerner61]

Originally Posted by Vin Man

Thank you. These directions are for programming the key fob - the lock, unlock and trunk release buttons. The fob on my second key works as I followed these instructions originally. However, the key still does not start the car.

I believe there is a transponder in the key. The ECU needs to know what the transponder key number is so that the computer will allow the car to start with the second key.

How can I program the ECU to accept the new key when I don't know what the transponder code is? I was hoping there was a way I could connect my computer to the OBD port, but the key in the ignition and tell the computer to add the key.

Very good to know. I've never read about the keyfob functions (unlock, lock, open trunk) being separately programmed from the ability to link to the ECU and start the vehicle. Good to know....yet it seems DIY ability to code the key to the ECU may make it worth the $200 or so (wild ass guess) it would cost to have someone else do it. Sucks.

[Vin Man]

Originally Posted by Our03z4

This explains about the programmer you need.

Holy crap. Thanks for the link. Maybe if I take the same meds the narrator is taking, I will be calm enough to dig into one of the circuit boards.

Definitely not a straightforward process as was mentioned in an earlier post.

[Vin Man]

Anyone in Gilbert, AZ done this before and want to give it a shot?

[brendanto]

The AK90+ is not that bad to do other than dismantling the module. I did mine this way a couple of years ago and upgraded to a flip key

[Coi]

If you can't program it yourself then try calling a mobile locksmith or taking it to an automotive locksmith and ask them if they do it. Tell them what type of car. I've experienced a couple times (my old mazda with active keyless entry/start, and a friend's Infiniti with keyless start) where people on the forums swore only the dealership could program keys but a mobile locksmith was able to easily do it for a fraction of the price. Locksmiths can program for the ignition as well as the doors, especially if you have an existing key.

[Vin Man]

Originally Posted by brendanto

The AK90+ is not that bad to do other than dismantling the module. I did mine this way a couple of years ago and upgraded to a flip key

I attempted it yesterday. I can't get the device to read my good key. Pretty frustrating but I'm not ready to give up yet.

I am surprised that there is not a way to code directly to one of the ECUs using Expert or Dummy programs.

[Vin Man]

This process worked. Did not need the AK90+

https://store.bimmernav.com/blogs/ho...5-e46-x3-z4-z8