Tesla rolls out FSD v14.3.9 (2026.27.6) with Automatic Collision Evasion: feature details and official release notes

Tesla (TSLA) has begun rolling out two major Full Self-Driving (FSD) software releases for HW4 and HW3 vehicles simultaneously. FSD v14.3.9 for new Hardware 4 and FSD v14.2 Lite for older Hardware 3 cars.

Both FSD (Supervised) software updates share the same firmware version: 2026.27.6. In the end-of-month update in August, Tesla merged the firmware of HW4 and HW3 for both versions of FSD.

Although both FSD branches share the same firmware version, the ‘Lite’ branches are refined to match the limited performance capacity of the legacy HW3 computers in legacy Tesla cars.

Tesla FSD v14.3.9 update brings the new ‘Automatic Collision Evasion’ feature to HW4 cars. This feature gets activated when a human is driving a Tesla vehicle to ensure safety in imminent safety scenarios (see release notes below).

Basically, the Automatic Collision Evasion (ACE) feature takes over the vehicle in any instance the FSD AI believes the human driver is not attentive or is sure that a collision is imminent.

Taking over the vehicle when a human driver is manually driving a Tesla is a new step forward in AI-driven safety.

It may seem like the AEB (Automatic Emergency Braking) feature in traditional vehicles. But it does much more, and Tesla will keep improving it as real-world data feeds the AI neural net for decision-making.

The word ‘Avoidance’ in this new automotive safety term explains a lot. This feature is AI-enabled, not something conventional. This system will not only warn a driver or apply the brakes, but it will also actively take over as the driver to mitigate the accident as much as possible.

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FSD v14.3.9 Rollout Status

Tesla initially began the rollout of FSD v14.3.9 with firmware version 2026.27.5. However, the automaker soon replaced it with the 2026.27.6 update, which also includes FSD v14.2 Lite for HW3 vehicles.

As of this writing, Tesla has released the FSD v14.3.9 (2026.27.6) software update to a limited number of Tesla owners. Apparently, this initial circle includes the Early Access Group of influencers and experienced Tesla owners.

Currently, the rollout momentum of FSD V14.3.9 is slow. Tesla will make it a wide release as it confirms the safety of the new release and as data flows back to the mothership and is analyzed.

FSD v14.3.9 (2026.27.6): Official Release Notes

The main line-by-line release notes for FSD v14.3.9 are unchanged from the previous version. However, Tesla has added Automatic Collision Avoidance as a separate feature in the release notes.

Automatic Collision Avoidance

Automatic Collision Evasion activates Full Self-Driving (Supervised) to try to keep your vehicle safe and then continue driving. It can engage in the following situations while you are driving manually:

Scenario 1: A frontal collision is imminent and braking alone may not avoid it.

Scenario 2: Your vehicle detects that you are not sufficiently attentive to the road (for example, reaching toward the back seat), or that Full Self-Driving (Supervised) may have been unintentionally disengaged.

See your Owner’s Manual for more details.

Tesla's Automatic Collision Evasion (ACE) feature introduced in the FSD v14.3.9 (2026.27.6) update. — Tesla’s Automatic Collision Evasion (ACE) feature introduced in the FSD v14.3.9 (2026.27.6) update. Credit: @Brand0n / X.

Full Self-Driving (Supervised) v14.3.9 includes:

Upgraded the Reinforcement Learning (RL) stage of training the FSD neural network, resulting in improvements in a wide variety of driving scenarios.
Upgraded the neural network vision encoder, improving understanding in rare and low-visibility scenarios, strengthening 3D geometry understanding, and expanding traffic sign understanding.
Rewrote the AI compiler and runtime from the ground up with MLIR², resulting in 20% faster reaction time and improving model iteration speed.
Mitigated unnecessary lane biasing and minor tailgating behaviors.
Increased decisiveness of parking spot selection and maneuvering.
Improved parking location pin prediction, now shown on a map with a (P) icon.
Enhanced response to emergency vehicles, school buses, right-of-way violators, and other rare vehicles.
Improved handling of small animals by focusing RL¹ training on harder examples and adding rewards for better proactive safety.
Improved traffic light handling at complex intersections with compound lights, curved roads, and yellow light stopping – driven by training on hard RL examples sourced from the Tesla fleet.
Improved handling for rare and unusual objects extending, hanging, or leaning into the vehicle path by sourcing infrequent events from the fleet.
Improved handling of temporary system degradations by maintaining control and automatically recovering without driver intervention, reducing unnecessary disengagements.
Unified the model between Actually Smart Summon, FSD, and Robotaxi for more capable and reliable behavior.
Actually Smart Summon max speed is now increased to 8mph (13km/h).
Help Tesla improve Self-Driving by selecting an intervention reason on the main screen after taking over.
You can now see distance traveled in FSD (Supervised) without an intervention. The Self-Driving App will also show your longest intervention-free streak.
Parking options now display on the map when arriving at your destination.

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Upcoming Improvements

Expand reasoning to all behaviors beyond destination handling.
Add pothole avoidance.

Acronyms used:

RL = Reinforcement Learning
MLIR = Multi-Level Intermediate Representation (MLIR)
FSD = Full Self-Driving
AI = Artificial Intelligence

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Tesla rolls out FSD v14.3.9 (2026.27.6) with Automatic Collision Evasion: feature details and official release notes

FSD v14.3.9 Rollout Status