Tumbleweed99

I just bought a 1999 Chevy Express 1500 High Top Passenger Van with 63000 miles. The anti theft passlock system keeps getting triggered. I replaced the battery, cleaned the grounds on the block and it started. 1 week later it won't start. I removed the steering column cover and snipped the yellow wire to the ignition sensor, won't start. Snipped the orange wire and spliced in yellow wire, won't start. Please note the security light is solid not flashing. Retraining techniques didn't work. Attempted both the ignition on 10 min, 30 minute and 30 minute positive battery disconnect events.Spliced yellow and orange back to original orientation, won't start. at a loss. I paid 3500 for this van and after reading all the nightmare stories about this issue, am afraid to have it towed to the GM dealership. Suggestions?

Ron6519

Does the,"Security" light stay on when you put the key in the, "on" position?
Or does it turn off after a few seconds?

Tumbleweed99

the security light stays on solid, not flashing. passlock reset does not work. disconnecting battery for 30 minutes does not work. resistor bypass does not work.
i'm at my wits end.

Ron6519

There's a relearn procedure I used when I switched out the ECU. Try looking it up. Concerns turning the ignition on and off over ten minute intervals, three times. If you can't find it let me know.
If there's a problem with the anti theft system, this won't work. You would need to find and correct the issue. You will need a scanner set up for this operation.

Tumbleweed99

Hey, I tried that and every other relearn procedure for passlocks, even disconnecting the battery for half an hour. I've ordered a scanner. thanks

Tumbleweed99

bought a scanner, no codes.

John Sparano

The anti theft system works on resistance in the start position. I used to install remote starters.When they first came out there were not interface modules . We used to measure the resistance across the 2 wires while holding the key in the start position and use a relay with a similar value resistor. An intermittant ignition switch could be the problem. You cannot cut the wires. The car thinks you are trying to steal it and locks up the ecu. Make sure you have resistance across those 2 wires.You can put the van in gear and turn the key so it dosent crank.

Chevy express 2005 Simon

Hello,

I am wondering if you solve the problem, i have a bit the same problem on a Chevy Express 2500, 2005 and it is killing me.
Randomnly the van doesnt start even if it crank well.
Randomnly the van stall while driving.
Every time it happen, it doesnt start if I crank it right after, but ALWAYS start if I wait 10 minutes and start back. (passlock learning procedure???)
I have seen the security light 2 or 3 time but the problem happened 50 times since 2 years. more and more often.
I have unplugged and plug back the small security wire on the key cylinder and now the security light is always ON. And van is starting anyway even with the light on.
Note that when it is not starting it is not hesitating at ALL, and when it do work after it start right on clean.
Thank for your help and time!

DarkYT

will your van crank at all? If not check the radio if there is one, if the theft lock is enabled on the radio (if one) is enabled the vehicle will be at a sudsed hault, thus you have to unlock it either by bypassing the security or getting a new radio and reprogramming, that or buy a new BCM

William Kisselstein

FWIW, a bad fuel pressure regulator will give the same symptoms as the passlock. Crank, no start. Spray some start fluid down it to rule that out.