Defect Petition · Closed
Battery Management Software Updates
Manufacturer: Tesla, Inc.
What NHTSA is examining
In a letter dated September 17, 2019, Mr. Edward Chen petitioned the NHTSA to initiate a defect investigation of certain Tesla Model S and Model X vehicles that received revised battery management software in one or more over-the-air (OTA) updates from Tesla, beginning in May 2019. The petitioner bases his request on vehicle fires that took place worldwide and OTA software updates Tesla made to the Battery Management System (BMS) of certain Tesla vehicles that resulted in loss of available vehicle mileage range and increased charging durations.On October 1, 2019, the Office of Defects Investigation (ODI) opened DP19-005 to evaluate the petitioner?s request. Information provided by Tesla in response to ODI's information request letter for DP19-005 indicated that a firmware update that may limit maximum voltage was installed in certain MY 2012 through 2016 Model S vehicles (subject vehicles). The voltage limiting firmware is a dynamic algorithm that is enabled in vehicles with high Supercharging use histories, which contributes to high usage stress to the high-voltage (HV) battery. Tesla sold approximately 61,781 subject vehicles in the United States and, through August 2021, the voltage limiting firmware had been enabled in approximately 2,062 vehicles. Through December 2020, ODI identified 59 complaints from consumers alleging reductions in battery capacity (52) or charging speed (7) in the subject vehicles. Log data from these vehicles showed that the voltage limiting…
Vehicles under investigation
Source: NHTSA Office of Defects Investigation records, updated daily. An investigation is not a determination that a defect exists; many probes close without a recall.