Where is VATS disabled - In PCM or BCM?

[usagoal]

I am working on an 01 Malibu, 49k miles, stock but has the infamous GM VATS/passlock intermittent no start issue. I am sure of this through other diagnostics and the incredibly low mileage on the vehicle.

Is the VATS system disabled through the PCM and not the BCM? As I understand the BCM looks for data from the ignition switch/mechanism, and when it is satisfied it has the correct data (correct resistance from the key/cylinder sensor) it sends a signal to the PCM saying it's ok to allow the fuel pump/injectors/ignition to operate normally.

I'm thinking about using my hptuners suite and laptop (plus 2 credits) to disable the VATS system on my buddy's car to avoid GM's antitheft system all together. Each part of this system is fairly costly and still unreliable according to the number of other owners with the same problems. We have bypassed the ignition circuit with some luck...but now it may be an issue with the BCM. He doesn't care if the vehicle no longer has antitheft as it is a 17 year old car.

I want to be sure VATS can be disabled in the PCM and not the BCM. This way a malfunctioning ignition sensor or BCM signal will not keep the PCM from allowing the vehicle to start since the VATS will have been disabled in the "higher" level of this system (PCM). Thanks for reading and I appreciate comments/questions/answers from somebody with more in depth knowledge on this subject than me!

[tek1229]

You can turn off Vats in the ECM and that should take care of the starting issue.. The BCM makes theft decisions and tells the ECM whether or not to let it run.. you'd be overriding that..

go ahead and read the ECU, it doesn't use any credits and make sure it's there, then use 2 credits if you want, turn it off and you probably will have to write entire for it to take..

You may end up with a security light on the dash when/if it fails theft again but it'll still start and run..

But for those malibu's I just jumper a 2.2k resistor between A6 and B6 at 24 pin gray connector of the BCM, relearn theft and bypass all the column wiring.. Those BCM's do have some issues though, seems to get some water in there from the hvac case maybe? seen them corroded when you take em apart..

[usagoal]

Thanks for the response tek1229. I needed reassurance that VATS is ultimately controlled by the PCM (ECM) and not the BCM. The hierarchy of modules talking to modules is something I don't want to take a guess on...especially if I'm going to use 2 credits to attempt to fix this.

I keep forgetting I can use my hptuners and read information without using credits....just never had the need for it yet until now.

I did the resistor trick, but it's in the column. I didn't have a diagram at the moment for the BCM pinouts.

Not too worried about the security light....we have ways to deal with that