Passkey of the bluetooth

Many things can cause this. fuses, sensors, wiring , or a bad computer. Best to have the codes read first. This points you to a cause. So you don't replace good parts.

To use your Bluetooth® wireless technology enabled phone in your vehicle, an initial one-time-only pairing procedure is required. To pair your phone, initiate Bluetooth® search mode in the vehicle. Then depending on the handset, initiate search mode or discoverable mode.* Once the vehicle finds the handset, a Bluetooth passkey is required to complete the pairing procedure.

You may choose any combination of 4 to 16 digits. Enter the passkey on the phone or vehicle, as prompted, and then the other device will ask you to verify it.

If it really is a 2006 or earlier year 335i Coup?, you need the vehicle's Owner's Manual. Since: "Vehicles require a fixed Bluetooth passkey for verification which is included in the vehicle's Owner's Manual."

You can obtain the manual from the dealer, when you provide them with your vehicles VIN-code, for a price of course.

From the BMW USA site:
Bluetooth FAQs

Try this - http://www.wikihow.com/Pair-Your-Bluetooth-Phone-With-a-2006-2009-Bmw-3-Series

http://www.fixya.com/cars/t2021653-locate_bluetooth_passkey_bmw_750li

Passkey default for bluetooth is 0000

Hello and Welcome to FixYa!

Follow the Instructions quoted on the forum link provided below and you would have access to your required pass key.
Click Here.
Best of Luck,

Please do RATE my solution, If found HELPFUL,

Regards.

I have the same car. The dealership wanted to charge me $155 to go into the computer and give me the passkey.

One of the techs just told me how to find it myself:

Inside the trunk, on the left side behind the DVD player, there is a box that sits at a 45 degree angle. Right above that box, there is a box that is shaped like a VHS tape. Unscrew that box and on the other side you will see bluetooth PK: and your four digit number.

That saved me $155 dollars and now I can talk hands free through my car.

on 750 and 750li 2007
open trunk remove carpet and wheel cover
remove 4 black pin from lock cover
remove 4 pin from left panel
remove silver latche 2 screws
remove the whole entire panel
look at the top you see silver box has sticker and "PK" and then a 4 digit code. those 4 digits following the PK is your bluetooth pin.

You need to go to your bluetooth menu in your phone and search for audio devices but at the same time you need to search for the phone in your i drive menu in the buetooth funtion . Be carefull and dont go into communication menu in your idrive press down on the button and scroll down. when the vehicle and phone find each other enter 0000 as the passkey unless you have changed it. Jst bare in mind just because they both have bluetooth does not mean they are compatable. the year of your car determines the level of software in your control unit in the car but updates are available from bmw dealers

If you go to your local bmw dealership they can connect their tester and access the bluetooth code from you vehicle in about 2 minutes. steve