You can connect your cell phone to your 2003 BMW even if the 2003 does not have an in-dash screen like many new BMWs. Syncing your phone with the radio allows you to answer your phone using steering wheel controls and talk on the phone through the car's speakers. Using Bluetooth is a safer way to drive while talking on the phone, and several states require a hands-free device while operating a vehicle.
Start your BMW and activate the Bluetooth on your cell phone. When the car is turned on, it is in "pairing mode" and will look for a cell phone.
Select "Bluetooth" on your phone's Bluetooth connections menu. This option may be called "Connections" and varies with the type of phone you own. Select the option that lets your phone search for Bluetooth devices. Consult your phone's owner's manual for specific instructions on how to complete this step.
Wait for your phone to locate your BMW. When it finds your BMW, you will see "BMW" followed by five numbers, which are the last five digits of your BMW's VIN number. Select the confirmation option when your phone asks you if you want it to sync with the vehicle.
Enter the "Passkey" number when your phone prompts you. You can find the passkey inside the booklet that includes your owner's manual. The passkey is four digits and will be listed after "PK," the abbreviation for passkey. You have about 20 seconds to enter the passkey on your phone before the sync process ends. If the sync is successful, you will see "Loading Phonebook" flashing on your radio's display screen. Your phonebook's contacts will load to your radio where you can access them. It could take a few minutes for your contacts to transfer.