Pairing the Z4

My recently purchased 2005 BMW Z4 has turned out to be a fine daily driver, as long as there's not snow on the road. But one thing that puzzled me was how to get my phone paired to the Bluetooth that was clearly built in. I'm a real believer in having Bluetooth in the car for phone use. I always cringe when I see an SUV bearing down on me, with a distracted driver holding a phone to his or her head.

In 2005, Bluetooth was quite new, and BMW chose to treat that pairing code like a bank PIN, with unique numbers to each car. The car was delivered with a slip of paper containing the code, but that was long gone. I did some Internet research, and could scarcely believe what I saw - I'd have to disassemble a good bit of stuff to uncover where they hid the code in the car. But I confirmed that fact with Rob Howry at Faulkner BMW, so this afternoon I dug in.



The inner trim in the trunk of the Z4 is stiff carpet, held in with their infamous plastic clips that are almost impossible to remove without breaking. These in particular were stupid, because you had to somehow get behind the part you're removing to hold the back side, or it will just spin. In the end, I just levered them out like everybody else does. Here's the view after the carnage:

Those are short boards on either side holding the carpet up, and the silver box with the black frame lying on top is the TCU - the Telematics Control Unit. That connects the car to your phone, among other functions. When I started, the silver box was bolted to the black frame, which was then bolted to the trunk back wall. The label I needed was on the face of the TCU that bolted to the frame, I suppose to keep it really really hidden.

So, once I had removed the frame and removed the TCU from the frame, this blurry picture was sufficient for me to get the four-digit PK# - the Pairing Key.

So, then I tried to pair the phone, and no joy. The radio would display "Activate Phone", and I would make the Bluetooth adapter visible and scan on my phone, but they wouldn't sync up. I put the trunk back together and gave up, but then later tried one more time on Google, and came up with the information that the car adapter would be named "BMW" plus the last five digits of the car's VIN - the Vehicle Identification Number.

Well, my phone had four of five of those floating around in there, since we've had so many BMWs in our lives. I checked the VIN, and sure enough there it was - it must have partially paired in an early attempt. I tried to pair that connection. It challenged for the key I had just found so I put it in, and sure enough, the phone paired.

It won't be a great solution, since there's no way a 2005 adapter will sync the 850+ numbers in my address book. But at least I can answer incoming calls safely, and initiate calls from my phone and then talk hands-free.

And while the Z4 has the floor, I'll report another experiment. Today I took it to our Mercedes dealership, which has one of those laser-guided touchless car washes. I wanted to see if the roof leaked when subjected to that high-pressure spray. The good news: it didn't! That gives me a lot of confidence that the car will handle whatever weather conditions it might encounter on road trips or whatever. And summer is coming...