Signs have emerged that Tesla is quietly introducing what is believed to be “AI4.5,” a new full self-driving (FSD) computer, without an official announcement.

On Jan. 26 local time, electric vehicle outlet Electrek reported that some consumers who took delivery of Model Y vehicles produced at the Fremont factory recently confirmed a new Autopilot computer fitted inside the cars that is called “Hardware 4.5,” or internally “AI4.5.” The computer was marked “AP4.5” or “AP45” inside the vehicle, and the markings were found to match a new FSD computer part number listed in Tesla’s electronic parts catalog. Tesla has made no official announcement about it.

Model Y owner Eric Sun (에릭 선) (@Eric5un) posted on X, formerly Twitter, that a 2026 Model Y AWD Premium built at the Fremont factory has a new front camera housing and an Autopilot computer labeled “AP45.” Other owners later reported similar cases, adding to the likelihood that AI4.5 exists.

Tesla hacking and firmware analysis communities are also watching the change. A well-known analyst, “greentheonly(@greentheonly),” said he first confirmed a new onboard computer update in Tesla’s software code. His analysis raises the possibility that AI4.5 has three systems-on-chip (SoC), unlike the dual-SoC architecture of the existing HW4.

If the three-chip architecture is confirmed as fact, it is interpreted as a design aimed at higher computing performance, improved safety and a “bridge” role before moving to the next-generation AI5 chip. Tesla has previously made a quiet shift from HW2 to HW2.5, and at the time it added an auxiliary processor without an official announcement.

The appearance of AI4.5 is drawing attention in particular as it coincides with delays to the AI5 chip. Elon Musk said AI5 would deliver 10 times the performance of existing hardware and be applied to vehicles in the second half of 2025, but the schedule was later postponed to mid-2027. The industry sees a gap of at least 1 year or more until mass production of AI5, and AI4.5 is seen as an interim solution to fill that period.

Still, anxiety is growing among consumers who recently bought HW4-based vehicles or are considering buying them. Musk has claimed unsupervised self-driving is possible with HW4 hardware, but the same promise was not kept for HW3 in the past. Tesla has acknowledged that HW3 vehicles require a computer replacement, but it has not presented a specific upgrade plan.

The market sees the emergence of AI4.5 as showing Tesla’s FSD software is outpacing the speed of hardware advancement, while also signaling that delays in AI5 development have become reality. Amid repeated hardware transitions and a history of unkept promises, experts advise that when buying a Tesla, consumers should judge based on the completeness of the current vehicle rather than future self-driving functions.

Hardware 4.5? @greentheonly @DirtyTesLa @NotATeslaApp “AP45” + part # 2261336-02-A Picked up a Fremont-built 2026 Tesla Y today (one of the last w/ Autopilot), mfg Jan 22. Includes new front camera housing + 16” screen, but no repeater/rear camera washers#HW45 #AI45 https://t.co/T2zqATkDex pic.twitter.com/ICb59aEirC