Tesla is unlocking Model Y Juniper cabin radar functions on older Model Ys as it offers free hardware replacement

The new Model Y Juniper facelift comes with the so-called 4D cabin radar that, according to Tesla's chief engineer Lars Moravy during an interview with Jay Leno, is for advanced occupancy detection purposes that include "size, height, weight, heart rate" measurements.

With the new 2025.2.6 software update, however, Tesla is bringing occupancy detection to older Model Y units which have had a cabin radar lying dormant since November 2021.

The 2022 Model Y and later iterations, as well the refreshed Model 3 and the Cybertruck, have a radar installed under the headliner just above the rearview mirror. It has just been sitting there for no apparent reason, but Tesla is now flipping its switch with the 2025.2.6 software update.

"The first-row cabin sensing system has been updated to use cabin radar, which is now standard in all new 2025 Model Ys," tips Tesla, clarifying for owners that their "Model Y was built pre-equipped with the necessary hardware" before they start wondering how come their cars come with a radar all of a sudden.

According to Lars Moravy, Tesla has added radar to the seat sensors used to determine occupancy, so that it can measure the size of passengers as well. This helps determine which airbags to deploy in a crash, among other safety enhancements.

The cabin radar on the old Model Y units will only be operational as part of a "first-row cabin sensing system," however, while the new Model Y Juniper comes with a 4D radar that also detects the back seat occupancy.

Not only that, but it can sense the breathing and pulse rates of the passengers, and have the car react accordingly. If, for example, a small child or a pet has been left on the back seat and their heart rate intensifies, the Model Y facelift will open the window or switch A/C automatically, and notify the driver via a Tesla app alert. If no measures are taken, the new Model Y can even call emergency services on its own.

It is not clear what part of these features will make it to the old Model Y, though, as for now Tesla is only turning on its radar for occupancy detection and dynamic airbag deployment, and the same will go for the Model 3 and the Cybertruck.

The old unit may not be capable of pulse or second row occupancy detection like the radar in the Model Y Juniper refresh, but Tesla has begun sending out surprise "hardware replacement" service invitations. The app notification subject reads "Cabin Radar Replacement," and Tesla offers to swap the unit for free with a service center appointment if the owner wants to download and install the "Spring 2025 software update."

Whether this means that some old Model Y units will be upgraded to the new 4D cabin radar that comes with the Juniper facelift, or simply that their old unit has been deemed defective and that messes up the software update, remains to be seen.

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