2000 C3500 security issue - strange - help

I have a 2000 C3500 crew cab dually. Since the vehicle was bought every now and again it would fire and immediately die. I was on the trail that it was a security Passlock II issue since I could send it through the relearn process of leaving key in ignition and in the on position for 10 minutes and it would then start.

I added an Autopage RS900 remote start alarm to the truck and with remote start I have no problems. It has gotten much worse recently and the ONLY way I can start it many times is with the remote start. If I use the key, it craps out.

So, I snip the yellow wire from the ignition cylinder and meter the resistance between it and the orange/black wire, make a resistor pack to bypass the Passlock II, and button it all up. It still does it. I went to a friends last night that has been installing alarms for 15 years and we double check it. With the yellow wire cut completely and no resistors, the truck would still start. Shouldn't be able to start with yellow wire cut if it has Passlock II. So, I grind the black plastic off the head of the key and sure as hell .... no chip. It isn't even a security key but yet I get a flashing security light when this thing acts up and it doesn't do it all the time. I use my valet key that came with the truck with no head (plain key) and it starts right up.

My question and it will take someone who has either had the problem or someone that is DAMN good with elctronic troubleshooting, is WTF? Here are the basics again

1. Fires and dies at times with flashing security light in dash.

2. Can go through factory relearn process and truck will immediately fire.

3. Yellow wire cut and truck still starts

4. No chip in any of the keys

5. Acted up before remote start was ever installed and remote start is one sure fire way to start the truck. It has a bypass module on the remote start which last night we discovered is pretty much useless without a security chip in the key.

Anyone that has had this experience and solved it, or has worked on a GM with this problem, PLEASE HELP!. I am putting the truck up for sale and do not want to sell it knowing this issue exists. I want to solve it and my brain, and those brains around me, are fried!

Need to go have the computer relearned. I could have told you there was no chip in that key.There isnt any chip in any of those gm keys with those trucks.A standard metal key will start that truck.

I would just reattach that wire before you take it in also.Your truck takes just a standard B102 Key blank.Alot of people are fooled and think they are chipped.

Thanx Jon

The wires are all reattached and soldered back to factory now. If the key is blank what is the computer reading for security out of curiousity. I am curious how it works now like the kid that takes all his toys apart.

Edited: 8/30/2007 8:44:07 AM by PleasuresBurban

With PASSLOCK, when you turn the ignition lock, a sensor in the lock sends a resistance code to the on-board computer. If the code isn't correct, the computer shuts off the fuel to the vehicle's engine.If an attempt is made to start a vehicle by a means other than a key rotation in the ignition switch, the Body Control Module (BCM) will interpret this start as a vehicle theft and disable the fuel injectors.

Basically this just prevents hot wiring.So either your comp needs to be relearned or at all worse a new ignition.Which will also have to be relearned to the computer.

BTW if thats your boat behind the dually its BADASS!

Thanx again for the help. That makes perfect sense with what is going on with the truck.

The boat isn't mine. I did all the marine installs at a audio shop in San Angelo and was also the pick up and delivery guy. However, that is the mack daddy of all the installs I did while there. Guy dumped like 15k in the audio alone.

how much you wantin for the dually?

2000 model 13k