While I am a relatively new owner of a MS, and don't have any experience working on it, I have quite a few years working on high voltage, high current electric vehicles. (Ok, not as high a voltage, and not as high currents as the Tesla).
I don't think that Tesla really anticipated this issue of Salvage Title Tesla's showing up in the mainstream, and for this topic to bubble to the surface, like it has. I also expect that Tesla is finding their way on salvage repairs, much as they worked their way through the drive train problems that ultimately lead EM to impose an 8 year, unlimited mileage warranty to the motor and controller, in addition to the existing same duration warranty on the battery pack.
I also have seen a couple of problems regarding the 12 Volt low error (but not in my MS). I am reminded of a Ford Technical Service Bulletin that basically says that after you replace everything else without success, you need to replace the wiring harness. I think the error messages are very vague, in particular to the MS owner / operator. However, The Service Center technician will connect up their specific diagnostics equipment and let it do the more detailed and specific troubleshooting. Electronics failures have been moving away from component level repairs and towards major assembly replacement for decades, and that's a very lengthy discussion in itself. However, a technician at a service center doesn't need to know the reason for the particular component(s)failure, as long as they can pinpoiunt the assembly that needs to be replaced. Now, unfortunately, the resources available at a Tesla Service Center, or at the factory, are not available, outside the network. The reason I bring this up is that Bjorn Nylund recently had an issue with his famous P85 (Millennium Falcon)which turned out to require the battery pack assembly replacement due to a faulty contactor inside the battery pack. Tesla replaced his 'B' revision battery pack with a 'D' revision pack, which also meant the contactor (which is insde the pack) was replaced, and under warranty.
I don't know what type of contactor is in the Tesla, but in the 2002 Ford Think that I specialize in, the contactor connects the high voltage, high current battery pack to the motor controller. If the contactor fails to operate properly, a wrench symbol is displayed on the instrument cluster LCD display, and the Think will not move. It's also important to note that this also serves an important safety function; if the motor controller sees a fault, it will open the controller, and display the wrench. I would expect that the contactor in the Tesla is probably a 12 Volt one, and if the 12 volt battery isn't working, neither is the car. Maybe the battery, maybe the contactor, maybe the vehicle is seeing a fault; I didn't see that you posted which revision of battery pack you have in this car, but several points arise (at least to me).
'If you have a 'B' pack, you might have an internal contactor problem. In addition, if your MS was even slightly impacted, it may be suffering from an impact or percussive failure of the contactor. As I recall, Bjorn showed his error messages in his video.... might be prudent to see if it closely resembles what you are seeing. He also stated that they remotely diagnosed it, and said it had to go back to the Service Center. Obviously, their remote access to the onboard diagnostics told them they had a contactor problem, and it was not going to be fixed there at the side of the road. Now, I also would expect that Tesla is NOT remotely looking at your vehicle to see what their systems are telling them is the problem. I would expect that Tesla is continuing to formulate their salvage vehicle policy, but are probably NOT wanting to call you saying that you have an issue that they are seeing, and then trying to extricate themselves if there could be more negative publicity or pressure from outside.
The last thought I have is that success for you and your salvage Ms will be directly related to it being a success for Tesla. Don't know if publicity would be what they seek, but negative publicity is generally only sought after by washed up celebrities that truly saying no publicity is worse than negative publicity. It might be a PR coup to be able to report that Tesla vehicles not have a superior rating in every facet of crash testing, but also in repair and return to operating condition of a properly repaired or rebuilt MS. Once your MS repairs are completed, it would be in everyones interest in having it inspected, approved, and back on the road. I'm sure that Tesla realizes that it's not in their best interests to have a BMW or MBZ repaired properly and back on the road, and yet a Tesla MS can't meet the same standard.
I have not looked under the 'hood' of my MS. I think that Tesla needs to get with the industry as far as dealing with Salvage titled vehicles. In California, to get a salvage title relicensed and registered for public use is a bit of a joke. It needs to be inspected and cleared by the California Highway Patrol, which basically inspects the lights, horns, and brakes for proper operation. This in no way verifies that any frame damage was repaired to any industry certified standard. I don;t know whether I feel I should applaud Tesla for wanting to ensure that the vehicle is repaired to their designated standard, or whether they are just reacting to try to keep a repaired or rebuilt Tesla off the road, (and possibly out of the news). When a Mercedes or BMW is repaired, the manufacturer does not have the final say on whether it meets 'their' standards'; why, one might even surmise that a repaired or rebuilt MBZ or BMW might never meet their standards.... 'we'll be happy to sell you a new one... maybe also a lingering question about loved ones and salvage titles".
I think that Tesla is evolving their approach. I think it's reasonable for Tesla to inspect the vehicle after repair or rebuilding, since I think there's 2 important benefits. The first is that the high performance car will continue to function properly and safely in it's continued function as a high performace car. Secondly, though, I'd be very surprised if Tesla didn't expend a few hours with their design staff and examine whether there are any deficiencies that might be resolved in future production. I know, I would, if I was in this situation and had the opportunity.
I also like to say I appreciate the postings on this thread. It's amazing what Tesla has done, and what can be accomplished by working with the public (whether it be their shareholders, owners, future owners, and even the naysayers).
Model S85 Owner, 3 months and 8600 miles