Tesla is back in court, this time over allegations its automatic software updates severely hobbled or completely disabled the batteries in Model S and X vehicles, with the only official recourse being a $15,000 battery replacement.

Four plaintiffs from California, Illinois, Michigan and Washington state who own new or used Model S or X vehicles filed the suit [PDF] late last week seeking class status for their fellow affected owners.

The named plaintiffs claim that, despite Tesla saying their batteries are supposed to last the life of the vehicle, the Musk-owned automaker "deliberately and significantly interfere[d] with the car's performance through software updates that reduce operating capacity."

In the example of the California plaintiff, the suit alleges that an over-the-air (OTA) update in late September of last year reduced his Model S's battery range from 270 miles (434km) to just 80 miles (128km) per charge and caused his car to broadcast a "BMS_u029" error message, which the lawsuit describes as an indicator the battery "is depleted or inoperable."

As his vehicle was still operational, Menlo Park resident David Bui-Ford said he was able to have a third-party auto repair shop undo the software update, which he claimed eliminated the error and restored the battery's original range, all for just $500 (£399). Subsequent inspection of the battery found no errors, the lawsuit said.

One of the other plaintiffs, Lucas Butler of Washington, said he received an OTA update for his Model S in March that completely disabled his vehicle. When taken to a Tesla dealership, Butler claimed he was told he needed to pay $20,798.56 to replace the battery. 

"Prior to the software update, Plaintiff Butler's battery range was approximately 255 miles per charge; now he is unable to operate the vehicle," the lawsuit claims. 

Third parties

According to the lawsuit, Tesla should have been aware that its software updates have a tendency to affect batteries, especially given a history of complaints about the issue and third-party products designed to undo bad software updates, something Tesla denies the possibility of.

One vendor of such a software rollback product quoted in the lawsuit, Hybrid ReVolt, claimed that only Tesla knows the reason why, beginning in August of last year, its software updates started causing the BMS_u029 error and subsequent loss of battery capacity to occur.

"Upon diagnosing BMS_u029, no known fault could be associated with the vehicle[']s battery pack. Thus it is unclear as to why the BMS_u029 error is being triggered. Tesla's solution is to replace the entire traction pack at a great expense," the suit quotes Hybrid ReVolt as alleging.

In addition to complaints and third-party products being available, the lawsuit details instances where Tesla was taken to trial over battery depletion allegations, and notes it moved to settle almost as soon as the case was brought.

The prior case mentioned in the latest lawsuit, which also happened in the Northern District of California, isn't the only such instance of Tesla quietly settling a suit alleging that software updates throttled batteries. The same thing happened in Norway, where owners of Tesla Model S vehicles litigated for harming battery life and charging capabilities in software patches released in 2018.

Tesla didn't even bother representing itself in that case, allowing the court to simply rule in absentia to award plaintiffs 136,000 kroner ($16,300) for their trouble, which should hopefully cover the cost of a new battery. Tesla was sued over battery throttling in Denmark as well. ®

https://www.theregister.com//2023/05/16/tesla_battery_patch_lawsuit/