When I disabled VATS and VATS diagnostic my car goes into limp home mode. On the scanner it is showing code 46, VATS failure.

Why is this happening? Isthere something that I missed?

 

Are you recalculating the checksum?.
Any your missing something if your still setting a code.

 

I am not familiar with the checksum so I left it alone. What is it and how would I change it and for what reason?

 

ok sorry for that reply, but I did a quick review of what a checksum is. I did not do it but I did however verify that the info. programmed on the new eprom was the same as what was in the buffer.

I will try the checksum and see if that solves it.

 

I reviewed the checksum of the file with the VATS disabled, and the file with the VATS enabled. The checksum is different for both files.

Just to check, I enabled the VATS function on the file that previously had VATS diabled, to see if the checksum would be the same as the file with VATS enabled, and it was. So I know that it is changing it.

The problem with my VATS is that under normal conditions (VATS enabled), the problem is intermittent.

Even after all of this the problem still occors.

 

So how exactly are you disabling the VATS? The proper way is to hit the "control word" that set the "bit switch" in the eprom.

 

In my Tuner CATS software, I go to the switch tables and uncheck VATS select and VATS diagnostic. Is there something that I'm missing?

 

What model of car, ECM and eprom?

 

I have a 92 Camaro Z28, 7730 ECM, and 27C256 EPROM.

I tried something different: I went back and created a new file with all of the same calibrations as the file that had problems. So far everything is working great. Thanks to everyone who helped, and hopefully this solved it.

 

Just when you think that things are back to normal, they change. Last night, after washing the car at the carwash, the VATS BS started occoring once again. I am to the point where I am just going to physically disable VATS.

My question is when you place the resistor in the wire so that the system thinks that the right key is in all of the time, do you have to use a key without the resistor chip in it or will it be fine to use the same key?