Originally Posted by mobileinstaller

ok first off changing the ignition switch and tumblers will do absolutely nothing sorry if you have already done this. there are three main components to the passlock II system the passlock sensor, the BCM, and the Ecm and of course the wiring in between. Odds are if this keeps happening and there is no other problems such as door locks freaking out trunk release just goin off then it's not the bcm if you do the relearn feature and it works the it is also not the Ecm. so you are left with the 3 wires that run from the bcm to the passlock sensor.odds are the passlock sensor is bad. now there are two solutions either go to the dealer and have the sensor replaced or bypass the system for good. any respectable mobile electonics installer should be able to do this no problem it takes me about 20 mins and i personally charge 40 dollars to do so hope this helps also if you are mechanically inclined in electronics i can send a diagram on how to bypass it yourself hope this all helps

Originally Posted by mobileinstaller

ok first off changing the ignition switch and tumblers will do absolutely nothing sorry if you have already done this. there are three main components to the passlock II system the passlock sensor, the BCM, and the Ecm and of course the wiring in between. Odds are Sorry can't figure where I'm suppose to type at. I really need a diagram please
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Originally Posted by mobileinstaller

ok first off changing the ignition switch and tumblers will do absolutely nothing sorry if you have already done this. there are three main components to the passlock II system the passlock sensor, the BCM, and the Ecm and of course the wiring in between. Odds are if this keeps happening and there is no other problems such as door locks freaking out trunk release just goin off then it's not the bcm if you do the relearn feature and it works the it is also not the Ecm. so you are left with the 3 wires that run from the bcm to the passlock sensor.odds are the passlock sensor is bad. now there are two solutions either go to the dealer and have the sensor replaced or bypass the system for good. any respectable mobile electonics installer should be able to do this no problem it takes me about 20 mins and i personally charge 40 dollars to do so hope this helps also if you are mechanically inclined in electronics i can send a diagram on how to bypass it yourself hope this all helps

Originally Posted by chevyp2p

Hell guys I have a problem similar to the one you are describing. The truck starts up but then dies after a second or so, however I don't get any flashing security light.

I have replaced the passlock module and did a relearn as recommended in alldata, but that did not solve the problem.

Could be this a passlock problem or should i start looking somewhere else in the truck?

Thank You.

Originally Posted by Quinton Morgan

If your truck is starting it is not a passlock problem look elsewhere cause the passlock stops everything mechanical it wont turn over nor will it engage.

Originally Posted by jondoe28

UPDATE: Did the below fix almost a year. Started acting up again about a month ago. Security light always coming, have to wait 10 minutes for passlock reset (almost every day). Had the below fix done again about a thousand miles ago. Works absolutely perfect again. No securit light, starts every time. My mechanic showed me the contacts, and they were badly burned again. He took a dremel with a brush and cleaned them like brand new. I think the problem is GM using inferior metals. Also had to fix my service traction control by cleaning the contacts by the wheels, more than once. Hope this helps someone else, sure has helped me.

Originally Posted by jondoe28

I'm happy things work normal now. I've been using my remote starter for 2years because
i kept getting passlocked out, and having the security on when i drive probably 75% of the time. What you're saying is the key switch has nothing to do with the passlock system at all?