96 GMC Yukon VATS/Passlock Question

[Texcuda]

I've recently acquired a 1996 GMC Yukon that I'm having issues with getting to run. I had to install a new ignition lock cylinder due to someone trying to steal it previously. At first it started up and ran fine; however, now it will only start and run for 2 seconds. Initially, I suspected a VATS/Passlock issue. I tried the long relearn procedure but I noticed the security light does not turn on at all. There was no bulb in the instrument cluster so I put one in but the light still doesn't come on. I've read conflicting info online as to whether it actually has VATS/Passlock. Can anyone clear this up?

 

[Schurkey]

Perhaps a moderator will move this thread out of ENGINES and into Audio + Electronics.

Runs for two seconds is classic anti-theft, but I thought that didn't exist until '98. Does the new bulb in the cluster actually work if put into another powered socket? Does the vehicle have an aftermarket security system, or remote-start system?

What is the fuel pressure at prime, and with the engine running for those two seconds?

Verify all "tune-up" parts and procedures.

Connect a scan tool, verify EVERY sensor and computer output.

 

[HotWheelsBurban]

I've recently acquired a 1996 GMC Yukon that I'm having issues with getting to run. I had to install a new ignition lock cylinder due to someone trying to steal it previously. At first it started up and ran fine; however, now it will only start and run for 2 seconds. Initially, I suspected a VATS/Passlock issue. I tried the long relearn procedure but I noticed the security light does not turn on at all. There was no bulb in the instrument cluster so I put one in but the light still doesn't come on. I've read conflicting info online as to whether it actually has VATS/Passlock. Can anyone clear this up?

Agreed, general consensus on here is that passlock didn't appear until 1998 model year. My '97 was built in September 1996 and it doesn't have it(one of the reasons I wanted it!).
The vehicle may have an aftermarket alarm or a factory option one, that mimics passlock.

 

[Caman96]

x3 on 1998.

 

[someotherguy]

I've recently acquired a 1996 GMC Yukon that I'm having issues with getting to run. I had to install a new ignition lock cylinder due to someone trying to steal it previously. At first it started up and ran fine; however, now it will only start and run for 2 seconds. Initially, I suspected a VATS/Passlock issue. I tried the long relearn procedure but I noticed the security light does not turn on at all. There was no bulb in the instrument cluster so I put one in but the light still doesn't come on. I've read conflicting info online as to whether it actually has VATS/Passlock. Can anyone clear this up?

If it's REALLY a 1996 model - confirm with 10th digit of VIN (T=1996) then it does not have Passlock. As others have mentioned, that didn't hit GMT400's til 1998 model.

Additionally, if your truck had it you would need the specific ignition cylinder that is used with a 1998 model, and you'd notice an extra connector and 3-wire harness in your steering column casting around the cylinder:

You must be registered for see images attach

So your problem is elsewhere. You may have an aftermarket antitheft system that is coming into play. When it runs 2 seconds then stops, are you able to re-start immediately? Or.....?

Richard

 

[Texcuda]

If it's REALLY a 1996 model - confirm with 10th digit of VIN (T=1996) then it does not have Passlock. As others have mentioned, that didn't hit GMT400's til 1998 model.

Additionally, if your truck had it you would need the specific ignition cylinder that is used with a 1998 model, and you'd notice an extra connector and 3-wire harness in your steering column casting around the cylinder:

You must be registered for see images attach

So your problem is elsewhere. You may have an aftermarket antitheft system that is coming into play. When it runs 2 seconds then stops, are you able to re-start immediately? Or.....?

Richard

It is a 96 model as the 10th position of the VIN is "T", and it does not have the additional harness & sensor on the far right of the lock cylinder as shown in the picture you attached.

Thanks!

 

[Schurkey]

Does the vehicle have an aftermarket security system, or remote-start system?

What is the fuel pressure at prime, and with the engine running for those two seconds?

Verify all "tune-up" parts and procedures.

Connect a scan tool, verify EVERY sensor and computer output.

???

 

[Texcuda]

???

Please clarify your original statements:



When you say "at first" do you mean "prior to the attempted theft" or do you mean "immediately after you installed the new ignition lock cylinder"?



OK, I understand this part ^^^

I'm trying to ascertain whether the symptom appeared immediately after the cylinder was installed, or instead appeared some time later.

This detail might be moot in light of previous posts, but it's something I've been wondering about.

Gentlemen, I do not need assistance with diagnosing a true mechanical problem. I am simply trying to ascertain IF a 1996 GMT-400 could have been factory equipped with Passlock/Passkey/VATS. I'm trying to avoid chasing my tail by looking for a mechanical problem that doesn't actually exist.

With that being said:
My brother bought this Yukon 3 years ago for my nephew. He let it sit and during that time because it had a misfire on cylinder 1 that he couldn't diagnose. During that time someone attempted to steal it by trying to hammer out the ignition lock cylinder. I put a new lock cylinder and the Yukon started and ran without shutting off.

I then had diagnose the original reason that my brother left it sitting for 3 years: a failed lifter. I pulled the Intake and replaced the lifter. Now the Yukon will only start and run for 2 seconds; just like a 98+ GMT-400 with VATS. Thus why I am trying to ascertain if this is a GM antitheft problem or a true mechanical problem.

 

[Caman96]

No!

General Motors Vehicles Equipped with PASSLock

The PassLock system was designed to prevent vehicle theft by disabling fuel to the engine if attempts are made to start the vehicle without the correct bitted key.

www.locksmithledger.com

You must be registered for see images attach

 

[Caman96]

It is a 96 model as the 10th position of the VIN is "T", and it does not have the additional harness & sensor on the far right of the lock cylinder as shown in the picture you attached.

This quote ^^^ answers quote below.

I am simply trying to ascertain IF a 1996 GMT-400 could have been factory equipped with Passlock/Passkey/VATS.