Tesla Model Y Hardware 4 Teardown Reveals Cheaper Ram, Missing GPU and Camera Connectors

By Kevin Armstrong
We get our first view at hardware 4.0 for the Model Y
We get our first view at hardware 4.0 for the Model Y
Greentheonly/Twitter

In a recent series of fascinating tweets, @greentheonly provided an unprecedented look into the internals of Tesla's new Model Y Hardware 4 or HW4. With his expertise and knowledge, Green shared detailed observations on the HW4's physical structure, board components, and the viability of retrofitting older models, giving the Tesla community much to ponder.

Breaking Down the HW4's Structure

Green's exploration of the HW4's complexities commenced with him acknowledging an "anonymous donor" for providing a chance to look inside Model Y's HW4. The serial numbers and other identifiers were blacked out. Green stated it was done to protect the donor after previous experiences, "Tesla is vengeful like this and went after the guy that did hw2.0 teardown by trying to deny warranty on unrelated repairs. Does not help that this new computer now has a (borderline illegal) 'warranty void if removed' sticker."

Delving into HW4's Core: Circuitry and Components

First up on the dissection table was the computer's physical form factor. According to Green, the HW4's form factor mirrors those of the S/X models, putting to bed any speculation around a potential retrofit to HW3 cars.

Moving deeper into the HW4, Green revealed that the board layout is similar to the HW4 on the Model S. However, as Green termed it, specific components, including the GPU and superior sound hardware, are now missing or depopulated. The use of cheaper non-Error-Correcting Code ram (ECC RAM) also seems to be a cost-cutting measure implemented by Tesla in this version of HW4 on the infotainment system side. Interestingly, this version of HW4 features two additional but depopulated display connectors, hinting at possible a possible second display in the vehicle.

Other distinguishing attributes of HW4 include a reoriented BroadR-Reach ethernet and the addition of a third, depopulated ethernet. Moreover, Green pointed out that the gateway chip has changed, too, with a different model from another vendor now in use. This chip, which was only seen in Chinese-made boards previously, seems to be a standard feature in all Model Y HW4 boards now.

Retrofitting HW3 to HW4: More Than Meets the Eye

The idea of retrofitting HW3 cars with HW4 stirred up quite a debate. According to Green, the concept may sound enticing, but it's not as straightforward as it seems. Modifying the vehicle to accommodate the new coolant pipe locations would be necessary for a retrofit, likely making this option more costly than simply manufacturing a new board in the old form factor.

Uncovering the Hidden Changes

Apart from the apparent changes, Green shared insights into some of the subtle modifications made by Tesla. For instance, the Texas-manufactured Model Ys feature a plastic "firewall" requiring a change in mounting methods for the new HW4. Despite the internal components remaining the same, the different mounting technique necessitates a unique part number for the computer.

Other changes include the absence of premium features like ECC RAM and the HD radar, which is reserved for the S/X models. Also, there's a reduction in the camera connectors in the Model Y, contributing to the list of differences in the HW4.

The missing camera connectors were for additional cameras, such as a front bumper camera. However, as Green says, the absence of a connector doesn't mean that Tesla won't add them in the future. In fact, if Tesla had no intentions of adding such features, they wouldn't be available on the board at all, instead of just being unpopulated.

Implications for Current and Prospective Tesla Owners

For existing and future Tesla owners, these findings offer a clearer understanding of what to expect from the HW4-equipped Model Ys. Notably, questions still linger about additional cameras and if and when newer models will receive them. The Cybertruck prototype already has a front bumper camera, so it may only be a matter of time.

While it seems that retrofitting HW3 to HW4 may not be feasible due to the cost and complexity involved, Green isn't entirely ruling out the possibility. He believes a different version could theoretically be created for retrofits, although it's unlikely.

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Tesla LFP Batteries Can Now Be Warmed up While Supercharging Using Innovative Feature

By Karan Singh
Not a Tesla App

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 Included FSD V12.6.1 and V13.2.4 in the Same Update: What Caused This and What It Means

By Karan Singh
Not a Tesla App

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.

While this update focuses on bug fixes, Tesla’s already working on bigger features for FSD V13.3, which we have already confirmed to include improvements to highway following and speed control.

FSD V12.6.1

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.

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