Ignition off, hold down the AS button and switch the radio on. Wait for a beep then release AS button.
Now enter the 4 digit code using buttons 1 to 4.
For example, if the code is 3584-
press button 1 three times
press button 2 five times
press button 3 eight times
press button 4 four times
If you accidentally push a button too often and go past your number just keep pressing, it'll come round again.
Now press and hold the AS button until it beeps.
Job done
bbc333
June 2009