Ducati MONSTER 821 2016 Owner's Manual page 138

After pressing button (4) to confirm the fourth and last
figure, the 4-digit code stops flashing.
Press button (4) for 3 seconds and the system will
check the entered PIN CODE. After 3 seconds:
- if the PIN CODE is correct (D), the instrument
panel shows "OK" flashing for 2 seconds,
followed by " N: " (new) followed by four flashing
dashes "- - - -" referred to the new PIN (F).
- if the PIN CODE is not correct (E), the instrument
panel shows "ERR." flashing for 2 seconds,
followed by "EXIT".
Repeat the procedures until you confirm all the four
digits of the PIN CODE.
Entering the "new" code:
1) Press button (4), one digit starts flashing
indicating "0";
2) Each time you press the button (2) the displayed
number increases by one (+ 1) up to "9" and then
starts back from "0";
3) Each time you press the button (1) the displayed
number decreases by one (- 1) up to "1" and then
starts back from "0";
4) To confirm the number, press the button (4);
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Repeat the procedures until you confirm all the four
digits of the PIN CODE.