Car Stereos: Installing an aftermarket stereo in a 2005 Impala, computer diagnosis, aftermarket stereo

Question
Hello.  I have just installed a Pioneer in my vehicle and I haven't been able to start it.  The message center displays "Security."  I went through the manual and it just said that the Security has been compromised.  I know that Impalas run their computer diagnosis through the factory stereo.  So, I used the wiring harness that connects the factory stereo to the aftermarket stereo and the vehicle.  I tested the stereos and the factory stereo's light came on.  But, the car still won't start.  Are other wires that need to be connected?  Do I have to do a reset or some kind?  Please help.  Thanks.

Answer
does the car has a factory alarm?. did you try disabling the alarm with the clicker?. (if you have it) some how you triggered the alarm and thats why it wont let you start the car. if you dont have the clickers or if you dont have any way to disable the alarm, take it to the dealership or to a certified shop and have them disable the factory alarm system. that should do it.

i hope this helps.

best regards,

Ed.