Don't have the access code

Do you mean the access code for turning off an alarm or arming the system before leaving? If so, NO. You would have to know the original code to even enter programming to change the access code. Contact your realtor and have them get you in contact with the previous owner. Find out the code from them. If they properly removed their code before moving from the house use the default code, 1234. Good Luck.

Depending on how option 54 is set the default master codes are 123456, 12345, 1234 or 123. The default Utility codes (1-Dealer, and 2-Installer) are 654321, 54321, 4321 or 321. If you get any of these to work, you can follow these steps to reset the memory to factory defaults:

1. Open panel cover and enter in code that worked from above.
2. Unplug the transformer and disconenct the battery.
3. Simultaneously press and hold - Cancel, ClockSet, and Minutes +.
4. Restore the power to the panel with the battery while pressing these three buttons. The panel should respond "Hello. System XX OK"
5. Release the buttons and plug in the transformer to the outlet.

call the security company (adt, brinks ) and they should be able to reset everything for you if you resign a security contract with them. After all the system is ment to be a monitored system