Pontiac Problems? Ask a Mechanic for Answers ASAP
Welcome, I'm Chris (aka Moose).
Is the vehicle not getting spark, injector pulse, or ignition spark?
So far the issue is pointing more so to the BCM to blame for the immobilizer system issue.
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BCM testing can be done with a scan tool.
Also a scan tool is what I suggest you use to proceed with this issue to see what is wrong from codes stored. If a description of the system is needed, see this link. https://dl.dropboxusercontent.com/u/90220402/VTD.pdf