How to change the master code on your Bosch alarm Step 1) Enter your current four digit master code followed by MENU Step 2 ) type in 1-1-0 into the keypad , the keypad will prompt you to enter a new four digit master code. Step 3 ) enter in your new four digit code and press ‘OK’ Step 4 ) the panel will ask you to confirm this code ,enter the code again and press ‘OK’ Step 5) press and hold down the MENU Button for 5 seconds this will exit and take you back to the main screen.