Tesla will recall every Model S and Model X vehicle that shipped with an 8GB eMMC NAND flash chip. Affected vehicles were produced between 2012-2018 (Model S) and 2016-2018 (Model X). Those produced after 2018 are configured with additional storage capacity and will not fail in the same fashion.
Any Model S or Model X with an 8GB Media Control Unit (MCU) will eventually fail, as we covered last month. This is not an issue that only affects certain vehicles. NAND flash is only rated for a fixed number of write cycles, which is to say, new data can only be written to the same physical sector of NAND a finite number of times. Tesla, unfortunately, shipped a number of vehicles with very aggressive data logging. It has since reduced some of these practices, but the amount of data the vehicle logs and transmits will inevitably wear out the NAND flash of any affected Model S or X.
When that NAND flash fails, so does the Media Control Unit. The driver loses access to climate controls and the backup camera. According to the NHTSA, the MCU’s failure affects the “rearview camera display, defrost /defog control settings, and exterior turn signal lighting.”
Tesla told the NHTSA that these failures don’t constitute a safety risk. The NHTSA letter states: “We note that your report states that Tesla believes that this matter does not have a safety risk. In our view, this statement has no force or effect in terms of Tesla’s obligation to undertake and complete the recall, and NHTSA does not agree with it.”
ET agrees with the NHTSA. Tesla’s innovations and willingness to approach car manufacturing differently is praiseworthy, but Tesla should have known that an 8GB eMMC unit wasn’t going to stand up to constant logging for years on end. Most vehicles don’t log nearly as much information as Tesla does and an 8GB NAND flash chip simply wasn’t going to cut it.
The number of vehicles being recalled is down slightly from the 159K figure being quoted in January. Still, the recall affects 134,951 cars. If you own one of them, you’d best get in touch with the company. The recall statement promises that Tesla will “replace the VCM daughterboard with one containing an enhanced eMMC controller, free of charge.” That language is ambiguous enough that Tesla could just swap the older MCU1 units with MCU2. Alternately, it could equip existing Tegra 3 boards with more storage. The Tegra 3 SoC was capable of addressing at least 64GB of eMMC memory. Microsoft’s Surface RT was sold in this configuration. Tesla may have outfitted its boards with 8GB, but it ought to be able to upgrade them.
Tesla’s recall will kick off on March 30. Vehicle owners will be notified by mail. Owners may also contact Tesla at 1-877-798-3752. The number for the recall is SB-21-21-001.