Question:
There is something wrong with my E90 key, hopefully you can help me with it. So here is the thing, I bought a BMW 335i second hand recently, which came with one key which was not remote control. It is an original key ordered in the dealer but it cannot open the car. The dealer told me that the CAS module is not from that car. What can I do? Below is a pic of the key. I just want to open the car with the remote control. Any advice would be appreciated. Thank you in advance.


Answer:
It seems the CAS unit was replaced in your car. If so the money you paid to dealer is now wasted. You need a new key that fits your CAS.
You need to by a blank key, and then you will need to borrow or buy a BMW key programmer or cable called BMW Multi Tool or other similar tools to add your virgin key to CAS EEPROM. Or you can find someone who has the tool to make a new key for you.
http://www.obd365.com/wholesale/new-b-mw-multi-tool.html

By the way, it seems that key in your photo is a valet key, which means possibly your car can be opened by someone else. You will also need to disable the old or lost keys.