2006 nissan frontier key code

hello guys i need some information here about the key code,the thing is  yesterday i  was tryng to help a friend with a problem on 2006 nissan frontier, he did a remote starter  on this vehicle and on his story is that before he even started to measure wires  ,he  disconnect the main ignition harness and then plugged it back in and tried to start the car and the car did not start anymore,on the dash its showing a red light with a car key, after  it the car did not start ,so he kept with his instalation ,of course the vehicle still doesnt start,but he thought it could get ok after a couple hours  but it didnt .now the car sits on the shop we tried everthing ,also we called a guy who does keys here ,he did start the car but after a few minutes the car does not start anymore ,any ideas thanks.

Ricardo, I remember you from before and I'm sorry I didn't get to respond to your private message before. Where in Massachusetts are you? Maybe I can find some time and you're not too far from Malden? Me ligue amanha sete oito um dois cinco quatro nove nove sete zero.