Mrsha-

Mode is the type of diagnosis you are asking the system to do. Mode 1 is entered by pressing the button once and waiting for the fault code to be displayed. Press the button twice and it goes into mode 2 that confirms the signal that you have entered, like moving the gear shifter and it will tell you that signal from the shifter is correctly received by the control unit. Press the button three times, and it goes through a sequence of activating components, like the shift solenoids. Mode 4 (press 4 times) you tell the control unit which component you want to activate. Mode 5 (press 5 times) is used to read out sensor values, like oil temp and gearbox RPM. Mode 6 (press 6 times) is used to reset the adaptive functions in the control unit. These are examples of trans modes. Engine modes run from 1-3, some systems don't use consecutive modes, like cruise uses 1, 2, 4, and 5.