Bluetooth connection Iphone 5 with BMW 5 series, latest model, fails

When connecting my Iphone 5 for the first time with my BMW 5 series i inadvertently entered 5 numbers as a code, now the car doesnt want to recognise the iphone anymore and i cant link the phone. Most of the time the phone doesnt even see the car, after restarting both sometimes the phone sees the car but the car says connection failed.

A second Iphone 5 is registered and works fine.

Please help, many thanks!