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Old 10-15-2019, 08:47 PM   #36
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Join Date: Jun 2013
Location: Nova Scotia
Posts: 517

2008 AURA XE
Default Re: Aura won't crank

Originally Posted by fdryer View Post
My bad as I'm trying to keep up with changes in security. PassKey III is similar to Passlock in that both use proprietary software to disable one or more EFI functions to prevent common thieves from driving the car away. Ions with Passlock disable the starter, S and L series from model year 2000+ with Passlock disable injector operation (starter still runs but without injectors the engine will never startup). My guess is PassKey III disables starter and/or injectors for the same protection.

imaddictded2u, I think you mean bcm, body control module. The bcm does almost everything else unrelated to the ecm's role to run the EFI system for the engine, including emissions control. The airbag and abs/tc/esc have their own electronic modules for completely separate controls All modules send error codes to the bcm for transfer to the OBD II port. As I mentioned previously, the bcm runs almost everything except abs and airbags; Passlock or PassKey III security, door locking/unlocking, remote keyfob, runs most of the instrument panel lights, all interior/exterior lighting, gateway for all error codes generated from every module including itself, outputting thru the OBD II port and provides software/firmware updating when GM uses their scantool ro communicate to every module. GMs scantool is the only tool for diagnostics, troubleshooting, testing sensors, programming remotes, communicate to every module. Other aftermarket scantools can have some or many of the same features as GMs scantool but still requires accessing GMs website for online support (subscription fee) to utilize all of GMs support.

The transmission control module (TCM) controls the electronically controlled xmission.
Not sure what you are referring to about BCM? Here is the schematic...for the Start curcuit and it's interconnections to the BCM and ECM
Here is the schematic of the PNP range selector switch and its interconnects with the TCM and ECM.
I find it odd is that none of the service info for troubleshooting a no crank mentions anything about the immobilizer as one of the possible causes but a crank/no start does list the immobilizer cutting off the injectors as a potential cause. This is why I question whether the immobilizer stops cranking. I'll see if I can get confirmation.
My $89.95 Launch EasyDiag scantool can read, graph and create reports for every parameter, every code, from every module in every OBDII GM vehicle. I also purchased the software module for $39.95 to do the same for all Honda vehicles and software modules are available for almost every make and model on the planet. It's an app loaded on my phone and uses a bluetooth dongle plugged in to the OBDII port for a wireless connection. All software and modules are updated for free every time the software is opened. It doesn't do all the TechII tool does but it's more than enough for a DIY tool.
2008 Saturn Aura XE 3.5L 4 spd
2000 Saturn SL1 1.9L SOHC (Retired)
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