LTxDave

OK, the VATS on my GS has left the car stranded. I've searched this site and the interweb and can't find a clear answer.

If I disable "VATS Select" will this disable VATS or do I still need a module to simulate the key?

vetteoz

On the tune?

That will take out the requirement for the fuel enable signal to be seen by the PCM ( nothing else needed ) but you still have to manually bypass
the starter enable relay also operated by VATS for the whole system to be gone.

WVZR-1

I'm guessing we're assuming it's the "resistance" visibility of the crank enable. I would think that the least expensive and more effective solution would be to install the correct resistance in the harness at the base of the column. The fuel enable is gone from the PCM through a tune and the resistance visibility is gone. If there's NOT a problem with fuel enable why "tinker" with it?

I'll be quite honest I always thought and have seen advertising VATS elimination and a flat fee. In an OBD2 PCM I thought/still do believe the entire VATS can be defeated. In OBD1 - fuel enable can be defeated in the "tune" but the "resistance" visibility is required for complete VATS defeat.

Interesting - I'll be "learned" I guess "soon"!!!

LTxDave

OK, where is the theft deterrent relay? I cannot find a location indicated in my FSM.

WVZR-1, I can certainly try just unchecking it in the tune and reprogramming to see if it works.

All I can say is it sucks to have his issue. I'm just glad it didn't happen yesterday while I was out of town or while I was parked somewhere not convenient to leave the car.

WVZR-1

I believe if it were me and I knew the resistance code of the key I'd just do the resistor at the column base and move on. I don't have a '96 FSM but I believe that when BCM's took over for CCM's the enable relays went away and the BCM was responsible for all of that.

I also don't know how easy it is to just program the PCM and that was the reason for my comment that if the fuel enable wasn't an issue why "tinker" with the PCM at all.

It is though an opportunity to "tinker"! There's a need to "tinker" I guess for all of us!!

LTxDave

I am trying to get the car home. I had to leave it at one of my rental properties. I don't have a spare key, but I do have software to program the PCM. I'm not just tinkering to tinker. I'm trying to solve a problem with what I have available.

WVZR-1

By now you've likely got your answer yourself by "trial and success or error"! I'm just on the side-line now as a cheerleader for your "victory"! I didn't read the urgency in the original post, just the interest in maybe if it were a possible solution. Sorry!

I'd say there's no reason NOT to attempt it then but if the key that you have can be read and display something reasonably close to a legitimate VATS resistance if the PCM programing doesn't work it's a solution.

Take the key by a GM parts dept and just ask that they "drop the key" in the VATS Interrogator and it either will display a valid code or it will NOT. If it does there's the resistor needed for the under-dash fix. Don't buy a key because if it's a failure of the cylinder then it would require a different mechanical cut if you elected to fix it.

There certainly doesn't seem to be a "cut and dried" answer out there!

LTxDave

Well with family in town this weekend, its been hard to get back out to the rental, but I was able to make it by there this morning for about an hour. The programming itself did not allow the car to start. I did get the FSM out last night and found the wire color for the TDR. I found a post on another site this morning indicating that the TDR was under the dash, near the steering column in the group of relays by the flasher. Found that before I had to pack up and come home to watch my 8 month old. I will take a ring terminal and some wire over in the morning to ground the TDR and we'll see where we are at that point.

LTxDave

I was able to go over earlier this evening and grounded the yellow/black wire going to the TDR. Cranks and runs!

WVZR-1

Good deal!!

vetteoz

Makes no difference
Both use a mechanical ( starter enable relay ) means of disabling the starter so either the relay has to be bypassed or as the OP has done grounded so it is functional.
Most bypass the relay completely as it removes a fail possible , no longer functional item from the car ;
given it's original function as theft protection is negated by being permanently grounded

WVZR-1

AS I mentioned in an earlier post:

Here I am learned!

Like I also mentioned initially that if it were a crank problem likely the fix would be a quick substitution of a correct resistor at the column base and not bother the "tune"! Dave could do the "tune" himself which was in his favor and it was the way he elected to accomplish it for starters and found out/confirmed for all that it's not able to be accomplished. That's good. He finished the temporary by-pass as needed and drove home!

We'll have to see how Dave accomplishes a repair if he does, was it a bad key, the cylinder not reading the key or was it the more frequent issue of a broken wire from the cylinder to the column base. OR ....

vetteoz

Not necessarily.
The resistor only fools the VATS system into "thinking" the correct key is being used.
If there is a fault in the VATS module ( in this case as part of the CCM ) or a mechanical fault with the relay and/or it's wiring from the module then the resistor
will have no effect on either fuel enable or starter.

There are plenty of documented cases on here ( esp with the standalone VATS module used on the earlier cars ) where the key is being read correctly
but the module has failed on the starter enable function and still does the fuel enable function.Bypassing the relay has solved the problem

WVZR-1

There is always a "not necessarily"! Always!

Did you miss "likely" and "quick"! I doubt there's a diagnostic tree that a novice DIY'r could accomplish any faster than the substitution. One more time "likely" and "quick"!

Now I guess you'd like to document your cases so have at it!!

BTW - an "early" stand-alone wasn't part of the conversation.