BobInCalifornia's Amazing E46 Traffic Pro install with iPod, Sirius, BMW Bluetooth Adapter for Phone and Home Made Interface adapter:

Traffic Pro E46: phone, Ipod and Sirius

What is this about?

After reading through Rachel's outstanding Becker Traffic Pro pages, I ordered my first Traffic Pro 4771 from Becker. It arrived complete with wiring adapter in a few days. The basic installation was easy, but there were more adventures to come...

I had a few goals for the installation

All of this was done in 2005, and has been reliable for two years now. Some of the techniques have been used successfully in other cars.

Disclaimer: Always get professional help. Never modify your car. Don't run with scissors.

Traffic Pro for E46

Start by reviewing the official installation instructions, you will find them on Rachel's web site. (Traffic Pro Users Page)

The reverse wire is in the right side footwell, behind the plastic cover. To attach the reverse wire, I looked in the big bundle of wires, found the blue & yellow wire, and used a volt meter to verify that the wire had 12 volts when the gearbox was in reverse, and zero volts the rest of the time.

Next it was time to remove the speedometer cluster (easy, just 2 screws near the top, the assembly just pulls out) and find the black/white wire. To be sure it is the speed signal wire, you may want to use the Traffic Pro diagnostic menu. The BMW E46 installation instructions also tell you which connector and pin to use.

For many BMWs, the Traffic Pro will fit right into the factory radio location. On the E46, you will need a plastic filler bezel from BMW, part number 65 90 0 139 640.

Next I installed the wiring adapter into the factory harness and connected the reverse & speed wires, installed then Traffic Pro GPS antenna (fits under the dash, see BMW instructions) and gently set the radio in place (not pushed in all the way).

After powering up the radio, entering the security code and going went through the installation steps the radio GPS found a 3D fix. The test screen for reverse worked, and the speed signal stayed at zero when parked, but went up when the car was moving.

So, that's all there is to a regular installation.

Better sound in the E46

The factory speakers in the E46 make sound, but might not reflect the outstanding audio quality which Becker radios are capable of. As the Traffic Pro has line out connections, it is easy to replace the factory speakers and trunk amplifier with another.

I had excellent results with a Zapco amplifier and aftermarket speakers. The Zapco includes balanced line drivers, which fit right above the radio and eliminate hum and noise that might otherwise be picked up between the radio and a trunk mounted amplifier. This installation was straightforward, and required runing a pair of Zapco balanced cables along the side of the car to the trunk where the new amplifier sits, and replacing the speakers.

Phone calls through the Traffic Pro

It is also possible to use a factory BMW Bluetooth cellphone adapter with the Traffic Pro. Verify that your model BMW can take the factory adapter by talking to your local parts person.

You will need the actual Bluetooth adapter (small metal box that fits into the trunk), a BMW bracket to hold it, a BMW pairing button that goes in your central console by the coin holder, under the armrest and a BMW microphone that goes near the driver side sun visor.

Have your parts person print out all the associated dealer instructions and go through the normal Bluetooth installation. Then, find the audio out wires in the trunk and then find them at the front of your car, by the radio. I ran separate wires in a shielded cable, but this might not be necessary.

You might need some crimp pins from Becker to add wires to the "C" connector at the back of the radio.

Route the two audio lines as well as the phone mute wire to the proper pins on the Traffic Pro, pair your cellphone to your car, you will be able to make and receive calls.

The Traffic Pro says "Phone" on the screen during a call. It knows to do that by a third wire from the Bluetooth box, which mutes the radio if it was on, and turns on the radio during a call if it was off. Incoming calls are easy to notice as the radio comes on (or mutes if already playing) and then you hear the phone ringing through your car speaker.

Sirius radio through the Traffic Pro

While BMW sells an OEM Sirius radio, it will not work with the Traffic Pro. I used an aftermarket Sirius receiver which includes a wired remote. The remote is exactly the right size to fit into the ashtray on an E46, which means it is invisible with the ashtray door closed. To see the name of a song playing on Sirius or change channels, just touch the ashtray door.

At first I just wired the Sirius audio into the Traffic Pro AUX input pins and was able to listen to Sirius channels. The Sirius antenna can go under the back shelf on an E46, there is even a little plastic bracket that fits the antenna.

Adding Ipod to the Traffic Pro

In the same way, it is simple to route audio from your Ipod into a Traffic Pro. Just use the three AUX pins on the back, and make up a cable with a 3.5mm mini plug to fit your Ipod. If you route your cable through the glove box, you can leave the Ipod out of sight.

Of course, that was not good enough, as it meant moving the audio cable between the Ipod wire and the Sirius receive wire. So commenced an adventure in Ibus electronics, designing a custom printed circuit and software, to easily switch between the Sirius and the Ipod right from the Traffic Pro.

A Home Made Ipod adapter

The E46 has an Ibus which is used to transfer messages between the radio, CD changer, cabin lights, window controller, clock etc. The Ibus sends the signals from the steering wheel to the radio to tell it to change volume. It also sends the signals from the steering wheel to the CD changer to tell it to change tracks. And it even carries the signals from the radio and/or Traffic Pro to tell the CD change to change tracks. All of this is done with computer messages sent over one single wire, the Ibus.

Above the E46 fusebox there is a junction box for all the car's Ibus wires. You can tap into the Ibus anywhere you see it.

There is a lot of Ibus information available on the Web. By tapping into the Ibus it is possible to listen to the commands to and from the Traffic Pro and steering wheel.

I decided to make a little adapter that would do the following:

To do this, you will need some electrical parts such as a TH3122 integrated circuit that interfaces to the BMW Ibus. By using the TH3122, we avoid collisions and insure proper signal levels. Using this part, you can attach a computer to the Ibus and listen to and send Ibus messages.

As this is a small surface mount chip, I designed a small printed circuit board. I wanted to be able to accept audio from both Ipod and from Sirius, so the board has a reed relay arranged for good audio shielding (independent from car ground) around the audio lines. The relay is run from the on-board computer, and can switches the AUX input on the Traffic Pro between two sources.

Audio from the relay goes through shielded cable to the CD player input pins on the back of the Traffic Pro. I don't put the Traffic Pro into AUX mode as in that mode none of the other buttons do anything. Instead, a low power ARM7 microprocessor module (from SparkFun electronics) sends out an Ibus announcement informing the Traffic Pro that a CD changer is installed in the car.

Now, the Traffic Pro thinks a CD changer is installed and the buttons all work. This way, you can change CDs by turning the knob (the CD list is fixed to just 1 2 3 4 5 6) and also you can change tracks. The Traffic Pro can go to track number from 1 to 159.

This was just right for using both Ipod and Sirius. By simply turning the knob while in CD mode, you can change between Ipod and Sirius, while leaving the Ipod in the glove compartment and the Sirius in the ashtray.

There is white plastic bracket that suits this kind of adapter under the glovebox, I bundled up the wires and installed it there.


I've been using the Traffic Pro for a little over two years now. It is just great, especially the navigation and using the avoid-traffic-jam button.

The Becker Traffic Pro radio sounds much better to me than the factory radio. There is no noise or hum at all, even with high power aftermarket amplifiers. You can hear nothing even right up at the speakers. This won't matter for everyone, but if you do want to have a better sounding car, the Becker can certainly help.

The Bluetooth phone adapter also works well. I pull over to take a call, but just being able to say "let me call you back" while the phone is in my pocket is much better than fishing for it.

Designing and construction the home-made adapter took a while. I used it as a learning exercise as I wanted to know how the ARM7 worked, and it was a good project for that. I recommend using a simple toggle switch for anyone comtemplating both Ipod and Sirius, it shouldl work just as well. You could hide the toggle switch in the ashtray, and if you want to listen to Sirius you will be opening the ashtray to change Sirius channels anyway.

My adapter also has a second serial port wired to the Ipod connector, and additional software that looks for track change messages from the Traffic Pro and translates them into Ipod track change messages. I spent a lot of time getting the software for that to work reliably, yet rarely use it. But there are times when you just get tired of a song on your Ipod and want to go to the next one. It is nice to just touch the Traffic Pro next track or steering wheel next track, so maybe it was worth the effort.

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