2002 X5 4.4 how to get codes
 

Do you have to have an OBD reader or can you read it with the key.

Yes, OBD reader

A generic ODB reader will get you industry-standard engine fault codes. For anything more detailed or for other modules you'll need a fault-code reader specific to BMW that's correct and compatible with your model and year.

There is a wide range of readers and capabilities. Some are wired some wireless. There are readers that connect by bluetooth to phone apps that are quite thorough and easy to use and $100 or less. Torque and BlueDriver are a couple of examples. The INPA suite BMW software is great though more difficult to use and requires a windows based computer.

Thanks for the info.

Sometimes they do not work...
Mine doesn't work....shall buy new one :D

If you brought that on Amazon Prime, just return it. I have purchase many bluetooth OBD II readers/scanner from Amazon, and they all worked.

Seems like the start up process is different with every one I have. Might check that.

I have the ELM327 module that connects via wifi. It works well. It's a bit of a trick to email the log files because the wifi does not connect to the internet, and it shuts down the 4G LTE. There's a trick to sending an email to myself, but once I figured out what the trick is, it's pretty easy.

I picked up an iCarsoft i910-II. Haven't tried it yet. Been to busy.