Some "detections" have occurred. Knowing a little more than most about battery technology and being an engineer, I think it's complete hogwash. The software may detect poorly performing cells, which are unlikely to be related to any fire potential, but that's it. The fact that the cells in the pack are tied together in sets of 3 and the existing sensors lack high resolution, means it's not possible to detect defects. If you isolated a cell (complete disassembly of pack) and used high precision laboratory equipment, you MAY be able to detect the defect.
It clearly detects something, since it has flagged some folks' batteries for replacement. And GM is not only spending money to have this software installed but they're telling us that with this software they no longer recommend any charging restrictions. I think that in practical terms those facts are worth something to a lot of folks.
While I do agree that I think it is not possible anything in this new diagnostics can directly detect the defects. I also believe certainly is possible for it to detect patterns in charging/discharging that seem to be related or have a higher chance of occurring when the defects are present. One of the advantages of onstar sending diagnostic details back from the cars would be the ability to find patterns in the cars that did catch fire. Also given the amount of time that has passed I expect they have also been able to locate batteries that have not failed that contained the defect and run tons of tests on them. GM actually has a pretty amazing facility dedicated to battery testing. So I think it is quite possible they have some patterns to look for that may not 100% mean a defect there but it could mean it is a higher likelihood so they would want to proactively replace that battery.
If this detection software was 100% foolproof, we might not get all batteries replaced but since this is a temporary measure and they are going to replace all the batteries anyway, I'm sure it is tweaked to detect the slightest abnormality (i.e. have way more false positives than false negatives). They seem pretty much convinced that it is good enough to allow customers to resume "normal" use of the car (albeit at a reduced capacity).
Yeah I expect if they thought they could 100% identify they would not replace everyones batteries. So anything they detect that makes them think a defect could be present is certainly to have some percentage of false positives.
It might be time to move on from this argument. There have already been a handful of 2020s that have become battery eligible, and the dealer-owned Bolts with the new 943 recall are all getting brand new batteries. It is pretty evident at this point that GM gave up on the idea of individual battery module replacement a long time ago.
Hey, I don't have the power to force anyone to believe or not believe anything. Nor should I. I was just pointing out that the evidence for universal Bolt battery replacement is growing, and the reasons to suspect otherwise are dwindling.
