You're correct. You can either disable it altogether or set a high and low threshold.There is a setting on the jscan app that allows for there to be a range for the preassure. goes off if too high or too low. Mine is set to something like 23 - 32 or so... been awhile since I looked. At least that is what I think it does. It was the setting that made the TPM light the least annoying without turning it off.