BMW Replacement Key Programming

If you are in need of BMW replacement key programming, look no further – BOTR Auto Locksmith Ltd can certainly help. If you’re interested in seeing how it is done, keep reading.

Different BMWs are split into different systems. There are EWS, CAS, FEM and BDC modules. This job involved me programming a spare key to a BMW X3, which had a CAS4 module.

As an auto locksmith, key programming in general can be done via OBD (through the OBD2 port), however when programming the majority of BMW keys, it must be done via ‘EEPROM’.

Different modules carry different risk, and CAS4 is one that should be done ‘on bench’ rather than through the OBD port of the car due to relatively high risk of data corruption. This means the first step is to get the module out of the car and get the circuit board out.

My next step was to read the data from the circuit board. This would usually require soldering of a wiring harness and removal of a few components, so I used an adapter which reduces risk to the module.

BMW replacement key programming

Once I had read the data, I was then able to open it up and edit it by writing a new key into it.

If successful, a success message will appear telling you you’ve successfully added the key.

As you can see on the screen, the last step is to test the key in the car. To check the key works before testing it in the car, you can use bench platforms. The test platform below is a Godiag.

BMW replacement key programming

They work by putting hooking them up to the circuit board/module, your programmer and an external 12V power supply. This makes the module think it is in the car. If you insert the key and the blue light lights up and stays on, it means the key is programmed.

It is always good practice as well to check that the original key works too.

This is what a successful CAS4 module key programming job looks like. If you need a BMW replacement key, BOTR can certainly assist.

I hope you found this insight interesting, and if you would like to learn more about other key programming procedures, click here. Thanks for reading!