Question [Q] Service Mode

Hey guys, i have a question. I'm trying to get into the service mode via the dialer by entering all the codes that i have found so far. None of them work ecept for one that shows promise but only shows a black screen with "Service Mode" at the top and it doesn't respond to any of the imputs from the drop down box. that code is - 27663368378 - There is another one that actually works but it just gives me the info on my network connections. Any help is greatly appreciated. Also I'm running stock, rooted, safestrapped, 4.4.2 kitkat. Thanks!