Prestige APS-786 issue

I installed this for a friend about 6 months ago into a 02 impala. Never any problems untill yesterday. According to him he said his car will not start even with the key. So I went down to his house disarmed the system and remote started it and started it with the key. Everything seemed o.k.. But I noticed when I arm the alarm the siren/horn does not sound, lights flash and doors lock .  Same  thing when the system is disarmed lights  flash and doors unlock. It seems as if the system is just operating as a keyless entry and remote start. When the vehicle is remote started I get the conformatin chirps so I know it is not the horn/siren. He told me he was playing ariund with the program/vallet switch trying to start the vehicle. Now I installed alot of these before and never came across this problem. I plan on looking it over this weekend if the weather pertains but I was wondering could he have put this in a mode by playing with the program/vallet button? Or has anyone come across this situation?

Thanks

dumb question, but is it in valet? ie. the led is on solid?

check to make sure he did not accidentally go in the menu and turn on slent arm and disarm

dei says to look at the ground for the problem, but i told them it would be better to look at the car. lol

what kind of bypass did you use for the pkII

The led wasent on so I figured it wasent in vallet mode. I used a learning bypass for the pkII but that shouldent be the issue because the car remote starts. I will sheck the silent mode issue in the programming book.

Thanks