Hi Ethan
I am experiencing very similar with my VY ute project. Could be worth a read as I have been trying to resolve the issue for a few weeks now. The link to where we start discussing the start issue is
here if you are interested.
If he vin has been changed on the ecu and the vats disabled it doesn't necessarily mean that it has been linked - which requires security security authorisation on a Tech 2 or a high end bi-directional scan tool.
Once the key is turned to acc the dash lights up with abs fault, followed by check engine and then contact dealer and won't crank.
This is a good indication of the key not being read by the BCM or the BCM not being linked to the powertrain interface or powertrain control modules (PIM and PCM respectively)
From the manual - on vehicles with a GEN III V8 engine, the BCM polls the PIM and sends an encrypted BCM / key security code when the ignition is turned on. The security code is received via the BCM slip ring, or via the remote receiver in the event of no slip ring communication. The PIM compares the received security code with its stored security code and
if the codes match, enables continued engine cranking and sends a separate encrypted security code to the PCM.
When my key was working I could get this far. As you can't get it to crank then I suspect that yur key is stuffed, you have a faulty BCM/PIM or the BCM and PIM are not linked correctly.
Then the PCM compares this code with its stored security code and if the codes match, enables injector fueling to continue. The PIM returns an OK TO START message to the BCM, which tells the BCM to jump from SHORT LOOP mode to LONG LOOP mode.
I have plugged in multiple scan tools and can't get the obd2 port to connect either. This needs to be sorted as without a scan tool you won't eb able to determine what is happening inside the start sequence and where it is breaking down. The entire start/run sequence is coordinated using a serial interface between the modules. This could simply be something not being connected, or a broken fuse but at the other end of the scale is could indicate that the BCM is stuffed.
Unless you can communicate with the control modules getting it up and running is going to be near impossible.
Is the scan tool able to be powered up from the DLC?
So for my 2 cents the recommendations are:
Step 1 - Download the VT-VZ manual - you are going to need it to sort this **** out. You can download it from
here
Step 2 - Check the fuses etc and make sure you have power on both sides.
Step 3 - Check the pins at the DLC for power and earth. (you will need the pin out diagram from the manual)
Step 4 - Check continuity of the cabling to the BCM
If the cabling to the BCM is good it is good and you have power it is time to make some decisions on how to proceed. If you don't have a good earth, quality power or there isn't continuity between any element of the DLC and where it enters the BCM you need to get that sorted.
This should be plenty to get you started. I'll keep you informed of my progress once my new scan tool arrives (I have a clone Tech 2 but can't link modules or program keys).
Cheers n Beers
Jolls
