86 Silverado LS1

iTrader: (2)

Guys I need some help. I can’t figure this one out. 2001 Yukon 5.3 70,000 miles. We have owned it since 2002. You try to crank it up and no start. None at all. Like it is out of gas or has no spark. It has done this about 5 times over the last year. I have seen no pattern to it whatsoever. It is usually after a short trip and rest like a trip to the grocery store. You come out of the store and no start. The bad part is it wont stay broke long enough to find the trouble. It will always start back up after some time???
My first thoughts were fuel pump. I figured it was getting hot and when you cut it off it would not pump until it cools. So I change out the pump and the connectors for the pump. That didn’t fix it. Now I keep a fuel pressure gauge in the truck in case I can get it on there when it won’t start. Well, last night it happened again. We came out of the restaurant and no start. I put the gauge on the fuel rail and it has a good 60 psi. So I start thinking about spark. Could it be the factory security system?? I did notice the security light in the dash on last night. Anyway we were using her keys in the ignition but we unlocked it with mine. So just to try it, I took her keys out and tried mine and IT CRANKS!! Can the keys even have anything to do with it? What about locking it with the remote then unlock with the key? Can any combination of this trigger anything with the factory security system? Does the factory security system have the ability to keep the motor from starting? The security light in the dash seems to have a mind of its own. I don’t know what triggers it but it does come of from time to time.
The truck does have a remote start. Can that play into this? I had it installed using the factory remote. You have to hit the lock button twice for it to crank. I guess it works off the old blow horn to verify lock thing. I don’t think this has anything to do with it but I’m not sure. This is the wife’s ride with the baby seats in it so you can see how this is a problem. Any ideas???
P.S. I know this isn’t a LS1 but I’m not exactly a member of any Yukon forums.

autotrix

iTrader: (5)

Yes if your security light is on then there is most likely a code stored. Yes it will keep the car from running too. Dont use locksmith made keys for extended periods- always use the factory key if possible, there is an embedded chip and or resistor in your factory key. If you are using the normal factory key there might be a problem with the system reading it. On the old GM pass-key systems it was easily bypasses by solding in a matching resistor to your key- not so sure about the new system.
Lockcylinder possibly? Ignition switches on these series also cause weird starting and electrical problems also....You might want to take it to a good shop and have them scan and diagnose. Good luck!

86 Silverado LS1

iTrader: (2)

Does anyone know if the 01 Yukons had a chip on the key? The one on my ring isn't factory and has no chip. It has worked thousands of times. But there is something wrong somewhere. Ideas????

alamantia

iTrader: (10)

im pretty sure that if it was a vats key issue it wouldnt crank

01WS6/tamu

iTrader: (37)

The silverados and sierra's including the sub and hoes do not have a secuirty key. It is a standard key, passlock is the name of the system your truck uses and it is built into the ignition lock cylinder and not the key. You will need someone with a tech 2 to scan the bcm to see if it has any security codes stored. However, if it is the passlock the pcm will have a I think P1632 theft enable signal not received or incorrect. Check back then post here or pm if you want I'm a dealer tech.

Levman74

iTrader: (3)

I dealt with this problem with a rendeavous, no crank no start interm. and then one day it would not start at all, had the security light on, and had a code or two, turns out it was the security module that surrounds the ignition cylinder that excites a chip inside the handle of the key to verify a valid key. had to replace and reprogram, and it was good as new. but hey, what do I know...

86 Silverado LS1

iTrader: (2)

The light is back on today??? Its on with both keys. Anybody know what this thing does...and why?

sroach20

iTrader: (31)

i had a 99 silverado with the same problem. i dont remember if 01 was when they went to the returnless setup, but my problem was the fuel pressure regulator. the diaphragm cracked, it started leaking, and caused the injectors to run wide open. this would make it hard to start at first because the engine was flooding. it happened when i tried to start it without it sitting for a while. the security light flashed also. if yours has the fuel pressure regulator on the fuel rail try pulling the vacuum line off and see if any gas comes out.

01WS6/tamu

iTrader: (37)

You need to get it scanned and see what codes it has. If the light is on it set a code. Once you know that you can go from there otherwise you are just wasting time. You need to scan the BCM and look at the security codes, you need a tech 2 for this though. The keys as a mentioned earlier are normal keys nothing special about them. It also does not use the trasciever around the lock cylinder like the rendezous does. It uses a resister embedded in the ign lock cylinder that is independant of the keys. On most of the tahoes I have had problems with it has been the lock cylinder itself. However, it would be accompanied by a no start. Bottom line DTC's and go from there.

86 Silverado LS1

iTrader: (2)

Thank you. Scheduled a scan.

86 Silverado LS1

iTrader: (2)

OK. got it scanned and it had 2 codes.
1) B2960 Security system data wrong but valid
2) B2961 Key in ignition circuit fault

My buddy is getting with alldata. Anybody had any experience with these?

01WS6/tamu

iTrader: (37)

Replace the ignition lock cylinder, reprogram passlock, ignore the key in ignition code that is just for the annoying door chime and has nothing to do with the passlock.

86 Silverado LS1

iTrader: (2)

10-4
Thats the same thing my buddy said after getting with alldata. Ill order one now. Or, Santa might bring me one.