QuestionI own a 2001 Grand Am GT. I have an aftermarket stereo and about two years ago I had an Ungo ProSecurity SR5000 installed. Initially, everything worked fine with a small problem of not being able to consistently lock the doors with the remote (happened occasionally). 6 months ago, during this past winter, my remote start would not start the car. The engine would turn over and just as you would think it was going to start, it would turn off. This would be repeated for a few times before it would give up. Once again, this would happen occasionally. A few days ago, it decided it wasn't going to start at all with no response from the remote (no locks, start or alarm) or from the key itself (just dead, no cranking). This was a problem I couldn't ignore so I took it to the GM dealer. After telling me numerous codes have been stored in my sensor module, including security alarms, I instructed them to disable the alarm and clear the codes. This appeared to work for a day but now it sits dead in my parking lot at work. I'm on my way to take it back to the dealer to, most likely, get the ignition switch replaced (a problem they assessed earlier). My question is, did my alarm system somehow cause my switch to fail or did it do it on its own and I can have my alarm hooked back up? Is it just a problem of incompatibility between my alarm and the internal security system or is there a way I can actually use the alarm I purchased? And why would it take so long for the incompatibility to start messing with everything else? Thanks for any thoughts you may have.
AnswerYour vehicle's factory antitheft system is known as passlock II. This system incorporates a resistor in the key cylinder that when the key is turned forward sends a 'resistance code' to the computer which then allows the vehicle to start. If the passlock system does not see the proper resistance code it prevent the vehicle from starting. To do a remote start in this vehicle you would need to install some sort of bypass for the passlock, whether it be a data module or a relay/resistor method of bypassing. Without knowing which exact bypass method was used I can not give a solid answer to this question.
Your door locks are controlled via a specific resistance as well. The problems you are having with the aftermarket system are typical of a bad/poor chassis ground connection.
The "Codes" the dealer is reading could be caused by a poor R value, which could also be cause be a poor system ground on the aftermarket system.
However, if the aftermarket system has been disconnected and you can still not start the car then that particular problem sounds as if the key switch may need to be replaced. So I would think the Ungo system would have nothing to do with the factory switch going bad.
I would suggest taking the vehicle back to the place that installed it initially as all the install shops I know of give a lifetime warranty on installation.
