Could someone who knows for sure jump in here.
I finally went to the dealer and asked them if my eBay key fobs would work or if I needed some code and they said AP8 only means I have the wiring harness and I need to buy a box and then have it programmed too.
WTF... does anyone know the truth and can set the record straight?
From my experience with a 2008 Tahoe LS with the factory AP8 keyless entry option:
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AP8 is the remote entry system but with all the provisions for the AP3 remote start option.
You need: The correct key fobs with the remote start button on them.
The activation code that comes with the AP3 kit.
A GM Dealer to do the programming, that's the ONLY way.
What happens: The dealer contacts GM on their dealership website and enters the code you got with the kit. GM then gives them another code to enter via their Tech2 programmer to activate the remote start function in your vehicle. They also need to reprogram the ECM and BCM computers to tell then that the vehicle now has remote start. It's all done with their Tech2 tool and the proper code that they get from GM.
Mine cost me $80 in labor from the dealership, the price of the kit seems to run around $150 or so IF you buy it from reputable sources. If you didn't get the activation code with your remotes you got screwed. It will not work without it.
Personally I think the factory remote start system sucks. I have a 2008 Tahoe LS and the range of the remotes (yes, fresh batteries) is terrible. Also the goofy "lock button twice before remote start button" is annoying, as it the fact that it will only run for 10 minutes and you can only hit the remote start function twice before you have to physically enter the truck and start it with the key. I'm looking to see if there is someone or some way to reprogram the system to extend the times and get rid of the two start limit. As for range, I could rig up some sort of external antenna that should help, from what I've found it seems the receiver for the system is located over the tailgate window in the roof.
If I had it to do over again I would go with a good quality aftermarket unit, and if I can't find any way to make the factory system work more conveniently that's what I still might do.
---------- Post added at 02:48 AM ---------- Previous post was at 02:40 AM ----------
UPDATE:
After once again being let down by the poor performance and range of the factory system I broke down and had a Viper 5704 system installed. I could not be happier. It fixes every shortcoming that the GM system had. Range is incredible, runtime actually gets the truck warm, the interior temp feature is kinda neat too, and the two-way confirmation is great. If I had a complaint its the fact that Directed only gives you one two-way remote with the system, the second one being a "companion" one-way unit. Personal opinion, if you pay that much for a two-way system it should include two proper remotes instead of cheaping out on the second one.