Why is NAND Endurance a Problem for Car Manufacturers?

All the code running advanced driver assist systems (ADAS), infotainment, performance features, and other core functionalities of a vehicle is stored on the flash memory of NAND chips. You’ll no doubt have seen how the current chip shortage is affecting the automotive market, but there’s another challenge surrounding these chips: memory endurance.

A flash device has a finite lifespan based on how many times you can erase and write to its sectors. When a vehicle receives an update, this is exactly what’s happening; the old code is erased and replaced with the updated code.

This means these chips are beginning to degrade and will, eventually, fail. This causes a knock-on effect throughout a vehicle with glitchy systems, non-functioning features, and potential safety issues, too. So, it’s in the best interests of car manufacturers to look for ways to either improve endurance or minimize the number of times this data is erased and written.

Why is NAND endurance a problem?

Worn-out NAND chips can cause a whole host of problems, something Tesla came up against in 2019. Failing chips caused rearview camera problems, as well as the absence of turn-signal chimes and other audio alerts. The problem affected 159,000 vehicles and the recall report showed failure rates of NAND chips of over 30% in „certain build months“ with failure trends accelerating after three to four years in service.

Tesla has been at the forefront of this technology for a long time so these problems begin to give us some insight into what other manufacturers could experience in the future. With so many vehicle features relying on these chips, there’s the potential for multiple car systems to be affected — from audio signals, as with Tesla, through to a vehicle’s ADAS features.

Where safety-critical features are involved, manufacturers don’t have the luxury of waiting around to see how long a component will last. A costly recall may be required as soon as the flash memory starts to show signs of failure. At the very least, a worn-out chip could prevent new erase-write cycles, which would make it difficult to deliver critical firmware updates.

Regular updates can cause problems

All modern vehicles require updating. For some, these updates focus on infotainment systems but, for more technologically sophisticated vehicles, the updates cover firmware and safety-critical features too. Whether delivered over cable in the garage or remotely over the air, current software update technologies erase the existing code before writing the updated code over the top.

With flash memory only able to withstand a limited amount of these erase-write cycles, the NAND chip begins to wear out. This leads to problems with the car’s features, as Tesla saw in 2019.

Changing the way vehicles update could be the solution

In order to prolong the lifespan of the flash memory, manufacturers must minimize the number of write-and-erase cycles each chip goes through. Aurora Labs has created an update method that, instead of reprograming the entire flash, writes an update to the next free space on the memory. This can be done up to 20 times before the data needs to be erased, prolonging the life of the chip.

On top of this, it minimizes downtime of the vehicle as the software can still run on the old code that’s contained on the chip while the update is happening. This improves the update process but could also increase the lifespan of a single NAND chip by 40 times when considering the potential for version rollbacks.

If you consider the recall report for Tesla that showed some chips failing within three to four years, this means Aurora Labs‘ Auto Update could increase the lifespan of a single chip from three years up to 120.

As vehicles become more technologically sophisticated, automakers need to consider the lifespan of these small parts. Using software to solve hardware problems isn’t new but it’s something that needs to be addressed sooner rather than later in order to avoid recalls and safety issues further down the line.

If you’d like to find out more about Aurora Labs‘ Auto Update feature, please get in touch.