From the Fiat 500 radio handbook:
When the radio is switched on, if the secret
code is requested, the display will
show the wording “Code” for about 2 seconds
followed by four dashes “- - - -”.
The secret code is made up of four digits
from 1 to 6, each corresponding to one of
the dashes.
To enter the first digit of the code, press
the button corresponding to the pre-selection
stations (from 1 to 6). Enter the
other code digits in the same way.
If the four digits are not entered within
20 seconds, the display shows the wording
“Enter code - - - -”. If this occurs, it is
not considered an incorrect code entry.
After entering the fourth digit (within
20 seconds), the car radio starts to work.
If an incorrect code is entered, the radio
will emit a sound and the display shows the
wording “Radio blocked/wait” to notify
the user of the need to enter the correct
code.
Each time the user enters an incorrect
code, the waiting time gradually increases
(1 min, 2 min, 4 min, 8 min, 16 min, 30 min,
1h, 2h, 4h, 8h, 16h, 24h) to a maximum of
24 hours. The waiting time will be shown
on the display with the wording “Radio
blocked/wait”. After the wording has disappeared
it is possible to start the code
entering procedure again.
.