Does anybody know if the VATS "code" for Third gen cars equipped with the system is in the prom or is it in the VATS control box. Thanks

 

Neither Technically. THe ECM needs to see 5volts on the VATS wire and it will work. But you can have the VATS option removed from teh chip so it will no longer be needed.

 

OK, the little Vats part of the key is a resistor, and in the VATS control box (that you find only on VATS equipped cars) is another resistor that when matched with one in the key. Together give you a voltage drop form 12 volts down to 5 volts that the prom can see, and allow the car to start? So the key value, has to be matched to the one in the control box.... put in the wrong key or hack into the steering column and turn the switch.......... no start. Am I close?

 

DO you have the key? If so... check the resistance within the chip in the key, then try to make something to match it and off you go, but yes your on the right track. Try a search and you will come up with loads of info to help you.

 

I guess what I am getting at is........... If I understand it right....... you can change proms (with the right F.I. programming for your year and application) all day long, and it won't lock you out on your VATS.

 

Yes the VATS can be removed from the PROM itself. Do you know anyone wiht a emulator?? If so this will be the easiest way to get rid of the VATS.

 

Hello Fbody fan 35yrs,

Correct me if I am wrong here, but it would seem that what you are actually asking is whether you can replace the prom chip in your ECM without the VATS being affected. If that is the case, the answer is yes, you can do that. When you put your VATS key in the lock cylinder, the code stored in the pellet in the key is read by a computer chip in the VATS control module. If the code in the key matches the code stored in the VATS control module chip, then a positive signal is sent from the VATS control module to the ECM which will then allow the fuel injectors and starter relay to function. If a negative signal is sent to the ECM, the fuel injectors and starter relay will not function.

The Trickster!!!!!!!!!!

 

Cruzin... Thank you for working with me on this, your help is appreciated.

Trickster..... You hit the nail on the head. My VATS is functioning normally, but I am going to be swapping some proms around, and wanted to get the big picture. I did do a search as Cruzin suggested, and found the chart that you posted earlier. It lead me to put an ohm meter on the resistor in my key, to keep for future refrence. The reading came up an exact match for one of the values in the chart.
Note: Here is the chart for anyone who is following this. The large number is ohms, but will show up as a decimal in kilo ohms for the 4 digit numbers. i.e. 7500 ohms =7.5 Kilo ohms

There are 15 different codes that GM uses in their V.A.T. systems. They are as follows, (1) 402, (2) 523, (3) 681, (4) 887, (5) 1130, (6) 1470, (7)1870, (8) 2370,
(9) 3010, (10) 3740, (11) 4750, (12) 6040, (13) 7500, (14) 9530, (15) 11800

Thanks again for the help you guys.

 

Glad to have been of some help. Sorry that I misunderstood what you were asking. I thought your VATS was inoperatble. But none the less we got things on track for you together.

 

Glad to have been of help Fbody fan 35yrs.

The Trickster!!!!!!!!!!!!!