Tesla has recently been making a spate of upgrades for legacy MCU1 vehicles, including FSD V12 for MCU1, but it also included a set of additional features in update 2024.26.3.1.
So let’s take a closer look at what Tesla has been cooking in the background for older vehicles!
Automatic Emergency Braking
Tesla has improved the Automatic Emergency Braking feature that was already available in MCU1 vehicles with upgrades from the 2023.12 software update, which includes automatic emergency braking while in reverse. What’s interesting is that although these features are available to other vehicles, they never made it into the release notes. Instead, we originally found them by searching through the 2023.12 owner’s manual. However, now that vehicles with MCU 1 are receiving the feature, Tesla decided to mention them in the release notes.
In the release notes Tesla states: “Automatic Emergency Braking now also works when your vehicle is in Reverse (R), not only in Drive (D). It applies the brakes if the vehicle detects an object in its path and a collision appears imminent.
Automatic Emergency Braking is on by default each time you drive.”
This specific upgrade likely also includes Automatic Emergency Braking for speeds over 100 mph in addition to working in reverse. AEB reduces the impact of collisions, reducing the likelihood of death or injury in a major collision. It’s fantastic to continue seeing Tesla focus on innovating in the safety department!
Reacting Perpendicular Vehicles
Another upgrade added to Automatic Emergency Braking recently was the addition of AEB reacting to perpendicular dangers (across) the vehicle path – for example, someone running a red light, or someone cutting you off. This is a huge improvement over the standard emergency braking that occurs for the vehicle in front. Tesla didn’t specifically call out this addition in the release notes for MCU 1 vehicles, but since those vehicles now seem capable of running the same AI model that powers FSD v12, we suspect this feature is also included.
In addition to FSD v12 and the Automatic Emergency Braking improvements, Tesla also made improvements to its Forward Collision Warning (FCW) system. When an FCW event occurs, the vehicle will now produced haptic feedback in addition to the audible and visual warnings.
These upgrades to Automatic Emergency Braking require HW3, which is a free upgrade for these vehicles from HW2 if the owner bought FSD.
At the end of the day, Tesla is clearly showing its commitment to continue to improve its vehicles – even older ones. Some of these MCU 1 vehicles with Autopilot HW 3 (originally HW 2) go back as far as 2016. This is a big deal for those who have been worried about the upcoming AI4/Hardware 3 divergence in FSD. Tesla’s continued work on older hardware is promising for users of Hardware 3 vehicles and MCU1 vehicles alike.
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Tesla’s been on a roll with Supercharger improvements lately, from the 325kW charging update for the Cybertruck, to 500kW with V4 Superchargers coming next year. While those improvements have been limited to the Cybertruck, Tesla didn’t put all their focus on their new flagship vehicle, but looked at their more affordable vehicles as well.
LFP Battery Heating
Tesla’s Superchargers can now heat LFP Batteries - those that are in the Model 3 and Model Y Rear Wheel Drive variants. This applies to Long Range and Standard Range models, which saw a limited run. This is another update included as part of the 2024 Tesla Holiday Update - which really arrived with a lot of unannounced new features and capabilities.
The change is pretty interesting - Superchargers of the V3 and V4 variety can now pre-heat batteries for Model 3 and Model Y vehicles equipped with LFP battery packs. That means those vehicles are able to get back on the road faster when it's extremely cold. Of course, Tesla still advises you to precondition before you arrive, saving drivers time and money.
Max de Zegher, Tesla’s Director of Charging, also commented on the new feature. Essentially, Tesla is inducing an AC (alternating) ripple current through the battery to warm it up. Keep in mind that Superchargers are DC charging. That means it is possible to get a cold-soaked LFP vehicle on the road 4x faster than before, assuming that it didn’t precondition at all and that it is in the worst-case scenario (below 0ºF).
In essence, Tesla is using some engineering magic to turn the circuits inside the LFP battery into an electric heater - and powering that heater through the Supercharger. An AC ripple current is a small oscillation in the DC charging current that generates heat through electrical resistance, warming up the battery. Those ripples are a byproduct of converting AC to DC and back - so Tesla is using the onboard charger to induce those ripples to warm up the battery. Definitely an innovative technique that’s really only possible with the versatility of the NACS connector.
We’re hoping Tesla can implement this across their full lineup of vehicles, but we’ll have to wait and see how it is trialed across LFP vehicles first and if it is even possible on vehicles with 2170 or 4680 battery packs.
Tesla launched two FSD updates simultaneously on Saturday night, and what’s most interesting is that they arrived on the same software version. We’ll dig into that a little later, but for now, there’s good news for everyone. For Hardware 3 owners, FSD V12.6.1 is launching to all vehicles, including the Model 3 and Model Y. For AI4 owners, FSD V13.2.4 is launching, starting with the Cybertruck.
FSD V13.2.4
A new V13 build is now rolling out to the Cybertruck and is expected to arrive for the rest of the AI4 fleet soon. However, this build seems to be focused on bug fixes. There are no changes to the release notes for the Cybertruck with this release, and it’s unlikely to feature any changes when it arrives on other vehicles.
FSD V12.6.1 builds upon V12.6, which is the latest FSD version for HW3 vehicles. While FSD V12.6 was only released for the redesigned Model S and Model X with HW3, FSD V12.6.1 is adding support for the Model 3 and Model Y.
While this is only a bug-fix release for users coming from FSD V12.6, it includes massive improvements for anyone coming from an older FSD version. Two of the biggest changes are the new end-to-end highway stack that now utilizes FSD V12 for highway driving and a redesigned controller that allows FSD to drive “V13” smooth.
It also adds speed profiles, earlier lane changes, and more. You can read our in-depth look at all the changes in FSD V12.6.
Same Update, Multiple FSD Builds
What’s interesting about this software version is that it “includes" two FSD updates, V12.6.1 for HW3 and V13.2.4 for HW4 vehicles. While this is interesting, it’s less special when you understand what’s happening under the hood.
The vehicle’s firmware and Autopilot firmware are actually completely separate. While a vehicle downloading a firmware update may look like a singular process, it’s actually performing several functions during this period. First, it downloads the vehicle’s firmware. Upon unpacking the update, it’s instructed which Autopilot/FSD firmware should be downloaded.
While the FSD firmware is separate, the vehicle can’t download any FSD update. The FSD version is hard-coded in the vehicle’s firmware that was just downloaded. This helps Tesla keep the infotainment and Autopilot firmware tightly coupled, leading to fewer issues.
What we’re seeing here is that HW3 vehicles are being told to download one FSD version, while HW4 vehicles are being told to download a different version.
While this is the first time Tesla has had two FSD versions tied to the same vehicle software version, the process hasn’t actually changed, and what we’re seeing won’t lead to faster FSD updates or the ability to download FSD separately. What we’re seeing is the direct result of the divergence of HW3 and HW4.
While HW3/4 remained basically on the same FSD version until recently, it is now necessary to deploy different versions for the two platforms. We expect this to be the norm going forward, where HW3 will be on a much different version of FSD than HW4. While each update may not include two different FSD versions going forward, we may see it occasionally, depending on which features Autopilot is dependent on.
Thanks to Greentheonly for helping us understand what happened with this release and for the insight into Tesla’s processes.