Reviewing the schematics for VATS, it shows no communication between the BCM and the PCM for the 2001 vette LS1. Unless the schematic is missing something, the only output of VATS from the BCM is a relay that controls whether the starter engages or not. That goes against all the posts that I have read and seems like a pretty poor solution for anti-theft since you could just push it down a hill to start it. There were a lot of circuits feeding into VATS, so it was thorough from that point of view.
This is a Porsche 928 installation, I will be attempting to start it for the first time in the next couple of days and I will report my findings. If the schematics are correct then I shouldn't need any VATS reprogramming, but that sounds just too good to be true.

If anyone has any details or opinions regarding this mystery, all posts are most welcome.

Thank you,
RR

 

The class 2 serial bus provides connectivity between the BCM and PCM.

Without disabling VATS in the PCM you can still get the starter to spin, but the PCM will not pulse the injectors.

 

Thanks Crain,
I found that the serial data connection to the PCM is on C1:58 and that the serial data connection on the BCM is on C1:B6, so that is how the information is communicated between the two, as you stated.
One clarification please. Many posts report that their car will run for about 30 seconds before the Theft Deterrent disables the system, are you certain that the 2001 vette LS1 won't run for a few seconds (without a BCM) for me before stopping or will it absolutely not run at all?

Thanks to any/all,
928vette

 

From the way I understand it... The VATS system works through the BCM.... You are correct in your statement... The BCM controls the functions of the doors being unlocked and receives a signal to tell the BCM to turn the the VATS on and off... But even when you unlock the door its not completely off... The cylinder lock for the key and ignition switch have a wire that leads to the BCM that looks for the ressitance that is within your key and cylinder lock....Thats why if you loose your key say with a GTO or Vette, you have to go to the dealer usually to get a key that matches the ressitor or have a lockssmith who is able to find it.... But the signal usually go from the key/lock, to the BCM, to the PIM, then to the ECM.....

Now the ECM and BCM never talk directly, for they do not speak the same language... The ECM talks to the PIM, then the PIM translate the ECM data into a language that the BCM can undertand and vise versa.....

In short, you need the ECM reprogramed... I know guys have used the bypass method, but its basically hotwiring the car....

 

Thank you for your response, Bozz. I couldn't find anything on 'PIM' in my manuals, I am guessing that the PIM was introduced with the LS2 engine. Nonetheless, your information was helpful and it looks like it's time to either send the computer in or buy hptuners.

 

The short engine run time when VATS is triggered is typical behavior, but I wouldn't count on it as an indicator that the engine is (or isn't) serviceable.

If this is a swap, there are lots of sensors you will likely need deleted in software anyway. I had to kill my fuel tank pressure sensor, AIR, aft O2 sensors, etc. VATS is just one more flag to set while you or your tuner are in there.