impala factory autostart no longer works

Our shop did a astrostart install on a 2007 chevy impala. The install went fine (the car is easy to do). But a few weeks later the customer noticed the factory autostart no longer works. When you try to start the car with the factory autostart, you press the lock button twice then hold the "start button" The parking lights flash but the car does not start like it used to. Any GM guys around? I have called local GM dealer and 3 people told me to try 3 different things (so that tells me they don't know how to fix the programming issue).

Is the check engine light on? I don't believe the factory RS will work if that's the case.C Renner's Auto Electronix

My service is cheap, quick, and good - pick any two

I confirm that. No factory RS with CEL on and you get 2 starts per ignition cycle. If you try to start a 3rd time you will get the same behavior, light flash but no start.

There are a number of things that can prevent the remote starter from working. If there any trouble codes in the vehicle, if the factory hood switch is defective or if the option has been turned off in the instrument cluster. The only way to know is to use a Tech II scan tool to see what is going wrong. Any GM dealer has this. It is possible, that adding the aftermarket unit, triggered codes that don't keep the check engine light on. Why is the customer even concerned though? He bought an aftermarket system aferall.sparky