PCM tune to disable VATS

[Tovar]

After eliminating all the usual suspects to a series of random no starts, I came to the conclusion that a failing VATS was the cause. No sense in replacing parts to this useless system...I heard, from this forum, that one can eliminate the VATS with a PCM tune. Since I, supposedly, already had a PCM tune for the turbo that I put on this truck, I asked the same vendor if he could also tune my PCM to eliminate the VATS. He said, "yes," so I sent the PCM to him. Got it back two weeks later, and put it in the truck. Truck started, but now the security light on the dash stays on all the time. It was my understanding that if the VATS was eliminated, no security light would ever illuminate. No function of the VATS would ever occur. Can anybody verify what is to be expected after a PCM tune to elimate the VATS. I have repeatedly asked the vendor who, supposedly, tuned my PCM, but he won't respond to my e-mails, which leads me to believe I got scammed.

 

[ak diesel driver]

You have both vats and passlock. Did you ask him to disable passlock?

 

[Tovar]

No. I thought the passlock was part of the VATS (why would they be separate...?). Only the VATS was supposedly disabled.

 

[ak diesel driver]

So my understanding is the vats sends it's signal to the passlock and then the passlock sends a signal to the PCM. So I believe you disable passlock to get rid of everything

 

[Rodd]

IIRC with a tune you can either have the passlock active and the light will go out or you can have it deactivated and the light will remain on all the time. It can be a PITA getting it synched up with the passlock active. I chose to have mine deactivated.

 

[ak diesel driver]

If it's deactivated right there shouldn't be any light

 

[Husker6.5]

Pull the instrument cluster out far enough to pull the bulb for the damn light if disabling passlock/VAT leaves it on. Problem solved if it is that annoying to have on all the time.

 

[Tovar]

Let me get this straight. If the VATS is disabled, and the passlock is disabled, then the security light will stay on all the time. If that is true, then it is possible that the tune I received to disable the security system occurred. I thought that if the light stayed on, then the security system was still active. Ak diesel driver says system deactivated no light, but Rodd says system deactivated continuous light. It would make sense if the vendor who did the tune would answer my emails asking this question, but, since he will not respond to my emails....I'm asking here on this forum. I'm trying to discover if the tune to disable my security system (VATS and passlock) occurred, so I can drive my vehicle without worrying if random no-starts associated with the security system will occur again. In other words, continuous security light good, or continuous security light bad......

 

[THEFERMANATOR]

You have both vats and passlock. Did you ask him to disable passlock?

Vats IS passlock. Vats=vehicle anti theft system, passlock is the style of vats these truck's use, and the vtd is the vehicle theft deterrent module that controls everything.

If the light is on, it's because the vtd senses a problem. Once vats is disabled, the ecm doesn't care about the vtd anymore. You said you had it disabled because it was causing problems, so the vtd is coding because it doesn't think it should be able to run, but it is. I would pull the bulb out if it was mine.

 

[ak diesel driver]

If we're going to be accurate our truck don't have VATS at all only passlock. For some reason I was thinking the sensor near the key was called vats. After rereading my FSM it's called the passlock sensor which sends a signal to the passlock module which in turn communicates with the PCM. Pretty sure if it's disabled correctly in the PCM the security light won't come on.
But if it's working with the light on pull the bulb

 

[ak diesel driver]

GM Passlock Anti-Theft Systems
The Passlock I system is considered the replacement for the GM Vehicle Anti-Theft System (VATS). The Passlock II and III (PK3) systems followed shortly after the introduction of the Passlock I system. The Passlock family of anti-theft systems are still in use today.
Reprogramming Passlock with a learning procedure
The Passlock family has two basic relearn procedures - a ten-minute procedure and a thirty-minute procedure - and which one you use depends on the system and what components have been replaced.
10-minute learn procedure:

1. Start from the ignition in the OFF position
2. Try to start the engine. It should crank but not start, and the security light will be flashing.
3. Release the key to the RUN position and leave it there for 10 minutes.
4. Turn the key to the OFF position for 20 seconds
5. Try to start the engine again. If it starts and runs, everything worked!
6. If the engine still won't start, repeat the above steps 2 more times (30 minutes total)

After the learn procedure is completed and the engine is running, the security light may stay on steady for a few minutes and then go off - this is normal. Depending on the system, replacement of key components will necessitate that a relearn procedure be completed. These include the ignition lock cylinder, Powertrain Control Module (PCM), Body Control Module (BCM), or Instrument Panel Cluster (IPC).
What does the warning light mean?
Operating states of the warning light on Passlock systems should be:

• On for bulb check
• Off when engine is running
• On steady if a fault occurs
• Flashing in the learn mode

Under normal operation, you should see the warning light on during bulb check and off when the engine is running—no message displayed on the DIC.
When the system detects a fault, the warning light will illuminate or a message will be displayed on the DIC, depending on the model. If a fault occurs while driving, the engine may or may not start after turning the ignition off. If a fault occurs when trying to start the vehicle, it probably won't start.
History of the GM Passlock family of anti-theft systems
In the mid 1990s, the first Passlock systems were introduced and are still used to this day. The Passlock I and Passlock II systems use a sensor in the ignition lock cylinder, which looks for proper rotation of the lock cylinder with the correct key. Upon successful rotation of the ignition lock cylinder, a code will be sent to the Passlock module.

 

[Husker6.5]

I'm so glad that my Burb and pickup do not have the anti-theft systems in them for several reasons.

 

[THEFERMANATOR]

VATS is the general term for vehicle anti theft system. GM has used PASSKEY, PASSLOCK, and MANY variations and progressions of it through the years, but VATS is always the term used in the service manuals to refer to the security system.

 

[ak diesel driver]

Not according to my fsm

 

[Tovar]

O.K. From all the above information, I think that the tune was done correctly. I will now drive the thing, and see what happens... Husker6.5 I couldn't agree with you more. If I had checked out 6.5's before I got one, I would have stayed away from the one's governed by all these electrical systems. Mechanical is always better. And these anti-theft systems are ridiculous.