It will still work-but I think if you unlock with the keypad instead of using the alarm fob, I believe the alarm will go off. The vehicle will still be armed and see the unlocking of the door by keypad as an intrusion (I think). I have not gone over this with the guy to make sure, and probably won't have the chance since wife is dropping it off. If the keypad disarms the alarm-that would be great. I commonly lock my keys in the truck and use the keypad to get in, just so I don't have to carry them (ie, out in the boat, out in the woods). But I will find out tomorrow. Not even sure what type of system they are using. I just know I wanted 2-way so it told me when it started instead of having to go to a window to see if it did.