Security Light NOT coming on 98 Silverado
 

Hello All,

This is my first post so please excuse the noobness. I have a 1998 Chevy C1500 5.7. Bought the truck a couple weeks ago and the security light NEVER came on. The truck started and ran perfectly until 5 days ago. Disconnected the battery to work engine grounds, The Big 3 etc and it started to drizzle. closed the hood and called it a day. The next day came home late from work so didn't work on the truck till the following day. Hooked the battery up went to move the truck and then it hit. Crank, turn over run for 1.5 seconds and then die. Checked the usual suspects, fuel psi and spark etc. and after dealing with a pass lock issue with my Canyon came to the conclusion that that was the issue. Did all the prescribed resets, the 11 min, 10 min, 30 min etc multiple times to the T (6+ times each) to no avail. Security light never once came on. Got a picked cluster to pilfer bulbs and rule out the cluster as being at fault and tried a few times again. (Light still not on) Dug in the dash to check the Passlock module, its gone. Apparently it was running the whole time without it. (months since engine was rebuilt by previous owner) Went to the junkyard picked a new module PN ending in 55 and tried it. Still no security light. Pushed on with the 11 min x3 reset 3 more times and threw in the towel. Got it towed to the local Auto electrical shop with no other info then the truck won't start and got a call back 3 hours later. Apparently the passlock module is not getting power. So he is ordering another one. Now I understand there are several PN's for these modules and they must match what's stored on the ECM, I think? Somebody please help. Also does anyone know if the correct Passlock module have to be in the vehicle for tuning software like HP tuners can tune out the vats system? Any info would be greatly appreciated.

I have similar issue but no one replied was there a solution?

It was a passlock vatts issue triggered from having my battery disconnected for too long. My mechanic ended up putting a resistor wired to the ignition the corresponds to resistance the computer is looking for. Video available on YouTube on the specifics.
Good luck Bro.

Same issue here. It's been bothering me for a long time, but I still can't find the answer

I am having the exact same issue. Batteries went dead on my plow truck, I disconnected them for the rest of the winter, now it starts runs a couple seconds, and dies. 80psi fuel pressure at the pump, clear filter, will run on starting fluid.

The security light never ever turns on. I have watched a few videos of the resistor bypass, and I did that on my kids 90 cadillac but you could measure the resistance on the key itself, this newer passlock the key does not have a resistor on it that I can see to measure.

Do you or anyone know what value resistor to use? or how to measure what it should be?

The resistor based Passlock system was no longer used beginning with the later model 1995 vehicles. You most likely just need to perform the relearn procedure. Use a battery charger during the relearn to make sure it completes correctly.


https://cimg1.ibsrv.net/gimg/chevrol...8aa50f6d4.jpeg
Check fuses 21 and 4 in the cabin fuse block to see if the security indicator comes back on. If not, set a timer for 11 minutes at each key cycle.