While you are setting up the Mastercode if you are not going to press the screen for 20 seconds then the system would time out with three beeps and an X pattern flashing, and you would have to restart the procedure.
Enabling the Mastercode:
As you keep the door open you would have to press the Program button until you see an illuminated Checkmark symbol (which would last for about 5 seconds).
Now, press the Checkmark symbol once.
After that type in the new Mastercode.
Then press Lock symbol just once and then enter the Mastercode once again.
Then press the Lock symbol once again.
Note: You will know that the programming is successful when the Checkmark illuminates and you hear a beep.
In case the programming is unsuccessful then you will find the X pattern flashing thrice with three beeps. And then check whether the Mastercode is not programmed already and try setting the Mastercode again.