- Memory chips in older Tesla Model S and Model X vehicles have been reported by many users to have a tendency to fail, causing difficulty using the central display screen and problems with charging.
- Car and Driver contacted Tesla for comment without response.
- The chip can get replaced free of charge—as long as the Tesla is still under warranty. If not, it can cost $1800 or more.
Flash memory devices, while compact and resilient, are not failure-proof. When failure happens to the memory chip inside any vehicle, the problems can be massive. It seems that the type of flash memory that Tesla used in some older Model S and Model X vehicles has had data written and rewritten to it enough times that the devices are causing problems with the cars themselves, specifically with the central display screen and ability to charge.
A quick glance at social media and YouTube reveals the problem is relatively widespread. This is not a surprise, since the type of memory chips that Tesla is using in its electric vehicles are only meant to be rewritten tens of thousands of times. With the amount of data that the flash devices—technically called embedded Multi-Media Controllers, or eMMCs—process in a Tesla vehicle, those tens of thousands of times eventually get used up, especially as Tesla's firmware image size has grown from around 300 MB to around 1 GB. All of this processing means that it's only a matter of time until most of these EVs start to suffer.
According to Rich Rebuilds, a vehicle repair channel on YouTube, Tesla changed the eMMCs used in its vehicles in 2018, but InsideEVs says that the second version of the eMMCs will also fail, eventually.
Right now, the Teslas affected by this failure are around four years old and older. Tesla CEO Elon Musk did say on Twitter in mid-October that things "should be much better at this point," but he did not specify if this means that the newer chips can handle more rewriting or if Tesla has somehow changed the code so it does not generate as many rewrites or something else. Tesla did not respond to Car and Driver's multiple requests for comment on this matter.
If a Model S or X is under warranty, then Tesla will replace the entire media control unit (MCU)—the motherboard that contains the eMMC—for free in case of a failure. But if the car is out of warranty, then it could cost a Tesla owner somewhere between $1800 and $3000 (estimates vary) to get a new MCU. But even so, this just sort of resets the timeline for when the rewrite limit is reached.
One repair shop told InsideEVs that there's no reason for Tesla to have programmed its vehicles to rewrite all of this data to the eMMCs. "There are absolutely zero reasons to log hundreds of MB per day to a small built-in flash chip," Tesla expert Jason Hughes said.