NHTSA Engineering Analysis EA20003: Loss of rearview camera
On November 20, 2020, the Office of Defects Investigation (ODI) opened Engineering Analysis (EA) 20-003 to investigate incidents of media control unit (MCU) failures resulting in loss of rearview camera in model year (MY) 2012-18 Tesla Model S and model year (MY) 2016-2018 Tesla Model X vehicles equipped with the NVIDIA Tegra 3 processor with an integrated 8GB eMMC NAND flash memory device. During its investigation, ODI learned that the expected usage life rating for the 8GB eMMC NAND flash memory device is approximately 3,000 “P/E” or Program-Erase cycles, after which the eMMC NAND flash memory device would become fully consumed and no longer be operational, leading to a failure of the media control unit (MCU). At a daily cycle usage rate of 1.4 per block, accumulation of 3,000 P/E cycles would take only 5-6 years. Historically, the expected life of a vehicle generally far exceeds 5-6 years of service. ODI believes that a 5- or 6-year life expectancy for a component integral to providing the driver with safety functions is insufficient. During our review of the data, Tesla provided confirmation that all units will inevitably fail given the memory device’s finite storage capacity. Tesla provided its own statistical model showing the number of projected weekly MCU repairs from 2020 to 2028, estimating that replacement rates for MCU failures will peak in early 2022 and gradually decline until (near) full part turnover has been accomplished in 2028. According to Tesla, for subject vehicles equipped with the NVIDIA Tegra 3 processor with an integrated 8GB eMMC NAND flash memory device, the eMMC NAND cell hardware will fail when reaching lifetime wear, for which the eMMC controller has no available memory blocks necessary to recover. With this failure mode, the only recovery available is a replacement of the eMMC device, achieved by physical part replacement of either the MCU assembly or visual control module subcomponent. Tesla provided information concerning the effect
US National Highway Traffic Safety Administration