2001 Silverado - Passlock Questions

[Murphster05]

Hello All,

I know this issue is all over, but I can't seem to find anything in regards to a Silverado with this issue. I have a 2001 Silverado with a 5.3 litre engine, 4WD. I also have a Clifford / Viper alarm with auto start. My truck is beginning to die at start up and flash security at me (passlock error). This happens sometimes just using the key, sometimes using the auto start. As I have a really nice alarm, I really just want to get rid of the passlock system. I did the resistor trick a couple years ago on an Alero and it worked fine.

That being said, I don't want to do something now that is going to increase the fees I pay at a dealer later should it not work. Is there anything I can do that will basically put this to rest forever, or do I have to go to the dealer and let the diagnose it and pay a few hundred bucks?

Thank you for your help.

[gmtech1]

What I have seen is that when the aftermarket alarm/auto starts are installed, they splice into the factory passlock system. This causes a higher resistance that the BCM sees and sets codes and starting issues. After I remove the systems, all is ok.

[Murphster05]

And if I wanted to keep the auto start... thoughts? It has been working for about 7 years now flawlessly, it has just recently started this BS.

Thank you for your reply!

[DeltaP]

If you want to keep the system you probably need to go back over the installation and check the connnections and splices they made,especially into the passlock circuit. Get rid of all those Scotch Lok connectors and wiring nuts and tape they're so fond of. The BCM reads the resistance of the circuit when the key is put in the key cylinder. If it doesnt match,no start. If its worked flawlessly for 7 years I'd say the integrity of some of those splices failed,raising the resistance of the entire circuit.

[j cAT]

Originally Posted by Murphster05

And if I wanted to keep the auto start... thoughts? It has been working for about 7 years now flawlessly, it has just recently started this BS.

Thank you for your reply!

you got 7 years with no problems . up here in the rust belt this is a problem after just a few years.

I agree with the other member , that you or the installer that put the alarm/remote start in should recheck all those splices and connections.

this should all be soldered and heat shrunk.. no half ass connectors that corrode.

[Murphster05]

Great, thanks for the feedback guys, I will look into this this weekend. I don't have heat shrink, is there any harm in going with solder and electrical tape? That being said, is there a way to completely disable this system on the Silverado?

Any idea where the passlock system would be on my truck? Yellow wire behind the stereo like the Alero or...? Need to hunt it down... Thank you for your responses and help.

[Murphster05]

If anyone knows where the wiring for this system would be that would be incredibly helpful... Thank you!

[gmtech1]

[gmtech1]

OK, so thats a little big. Sorry.

[Murphster05]

Thank you! Little big, but at least it isn't a little small!

[4x4junkie]

finally a schematic i can read without my glasses.

[ponchonutty]

Yes, the easiest and most perminate way to bypass that is to get a resistor (somewhere around 500-2500ohms works best) Cut the yellow wire. Connect one end of the resistor to the end of the yellow wire going AWAY from the switch. Connect the other end of resistor to the black ground reference wire. Then, take a jumper wire from the ground reference wire and the other end to chassis ground. Try to start the car. It shouldn't and the theft light should flash. Leave ignition on for 10 minutes or until that light stops flashing. Turn car off and count to 3. Try to start. Normally it will but if not, do the 10 min. trick again. It can take up to 3 attempts. If after 3 attempts it doesn't work, change resistance value and do it again.


BTW: On GM trucks, the ground reference wire will normally be orange/black.