2026-10-31
HW3 or HW4? How to tell which computer your Tesla has, and why it matters when you sell
Every recent Tesla has a self-driving computer behind the dash. Cars from the last few years have one of two: Hardware 3 (HW3) or Hardware 4 (HW4), which Tesla now calls AI4. From the driver's seat they look the same. When you sell, they're not the same car.
The quickest way: check the screen
On the touchscreen, go to Controls > Software and tap Additional Vehicle Information. The Autopilot Computer line shows which hardware your car has. Tesla added this screen in a 2024 software update, so any car that has been updated since then shows it.
Which Model S and Model X have which
- 2021 and 2022: HW3.
- 2023: either one. Model S and Model X switched to HW4 in early 2023 (ArenaEV, Feb 2023), so early 2023 builds have HW3 and later ones have HW4. Check the screen to be sure.
- 2024 and newer: HW4.
The 2023 model year is where most people get it wrong, because the year alone doesn't tell you.
Why it matters
- Full Self-Driving: both run FSD (Supervised), but HW3 cars get a scaled-down version called "FSD v14 Lite," while HW4 cars run the full version. The latest HW3 version, v14.3 Lite, arrived in October 2026 (Tesla Oracle, Oct 2026).
- The future: in April 2026 Tesla said HW3 won't be capable of unsupervised FSD. It has talked about upgrading HW3 cars whose owners bought FSD, but hasn't given a date or details (Not a Tesla App, April 2026).
- Value: a quick online valuation that only asks for year, trim and mileage can't see which computer your car has. We check, and our offer reflects the hardware your car actually has, along with seating, FSD, wheels and the warranty left.
Thinking about selling?
Tell us your VIN or plate and mileage, and a person who knows these cars sends you an offer, usually within minutes during business hours.
If you have a 2023, see what sets a 2023 Model X's value or a 2023 Model S's.