Diagsheet

2021 Tesla Model 3 · symptom sheet

Adaptive cruise or lane keeping misbehaves

  • 261owner reports
  • 7,000median miles
  • 3involved a crash

Newest report Aug 4, 2026 · checked Sep 9, 2026

447 of the 657 complaints on this car are about collision avoidance. 261 of those describe driver assist, which makes it the most reported problem on the 2021 Model 3.

Tick what matches of 261 reports

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35
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230
34

What got replaced

Owners who name the part that was replaced mention the software (37 reports), the camera (22 reports) and the radar (10 reports).

Recalls and investigations

3 recalls on collision avoidance cover the 2021 model year. A recall on the same system isn't always the same failure, so read the defect text.

24V-153Feb 27, 2024
Forward Collision Avoidance: Warnings:External/Pedestrian Alert

Tesla, Inc. (Tesla) is recalling certain 2013, 2018-2021 Model S, 2020-2021 Model X, 2018-2022 Model 3, and 2020-2022 Model Y vehicles. A factory reset muted the Pedestrian Warning System (PWS) sounds. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 141, "Minimum Sound Requirements for Hybrid and Electric Vehicles."

Risk and remedy
Risk: Pedestrians may be unaware of an approaching vehicle if the PWS sounds are muted, increasing the risk of a crash.
Remedy: Tesla released an over-the-air (OTA) software update, release 2023.44.30.14, free of charge. Owner notification letters were mailed April 27, 2024. Owners may contact Tesla customer service at 1-877-798-3752. Tesla's number for this recall is SB-24-00-006.
22V-317May 9, 2022
Forward Collision Avoidance: Automatic Emergency Braking

Tesla, Inc. (Tesla) is recalling certain 2020-2021 Model 3 and 2021 Model Y vehicles. The fisheye and narrow camera cable terminals were incorrectly installed in the cable harness connector, resulting in swapped camera views.

Risk and remedy
Risk: Swapped camera views can prevent the vehicle's cameras from detecting crossing objects and high-curvature lane lines, impairing the Autosteer and Automatic Emergency Braking (AEB) performance, and increasing the risk of a crash.
Remedy: Tesla Service will correct the swapped terminals and recalibrate the cameras, free of charge. Owner notification letters were mailed July 8, 2022. Owners may contact Tesla customer service at 1-877-798-3752. Tesla's number for this recall is SB-22-17-007.
21V-846Oct 29, 2021
Forward Collision Avoidance: Sensing System: Camera

Tesla, Inc. (Tesla) is recalling certain 2017-2021 Model S, Model 3, Model X, and 2020-2021 Model Y vehicles operating software version 2021.36.5.2. A communication error may cause false forward-collision warning (FCW) or unexpected activation of the automatic emergency brake (AEB) system.

Risk and remedy
Risk: Unexpected activation of the AEB system may cause the car to stop suddenly, increasing the risk of a crash.
Remedy: Tesla Service has released an over-the-air (OTA) software update, free of charge. The recall began October 25, 2021. Owners may contact Tesla customer service at 1-877-798-3752. Tesla's number for this recall is SB-21-00-004.

NHTSA investigations into collision avoidance on the Model 3

DP23-002opened Jun 29, 2023
Speed control · model years 2017 to 2023

Sudden unintended acceleration. Open.

NHTSA summary
The Office of Defects Investigation (ODI) received a petition requesting that ODI reevaluate its decision to deny DP20-001 on the basis that intermittent high electrical current demands on the vehicles' 12VDC systems may have caused some or all of the incidents examined by ODI in DP20-001. The petitioner bases this information on a review of open-source research and the DP20-001 denial. The petition and related materials can be reviewed at NHTSA.gov under the following ODI number: 11528471.
PE22-002opened Feb 16, 2022
Collision avoidance · model years 2018 to 2024

Unexpected brake activation. Closed jun 29, 2026.

NHTSA summary
On February 16, 2022, the Office of Defects Investigation (ODI) opened a Preliminary Evaluation (PE22002) to investigate reports of unexpected deceleration while driving with the adaptive cruise control system engaged in Model Year (MY) 2021 – 2022 Model 3 and Model Y vehicles manufactured by Tesla. The subject systems include Autopilot (all versions), Full Self-Driving (FSD) and Traffic Aware Cruise Control (TACC). These complaints have been colloquially referred to as “phantom braking”. ODI opened PE22002 to determine the scope and severity of the potential problem and to assess any resulting safety issues in the subject vehicles. The alleged defect is an unexpected and unrequested vehicle deceleration triggered by the subject system during subject system engagement. The alleged defect does not occur when the subject system is not in use and is separate and distinct from Automated Emergency Braking (AEB). During vehicle operation, AEB is actively monitoring in the subject vehicles regardless of subject system and its intervention is accompanied by audible and visual collision warnings. A Vehicle Owners Questionnaire (VOQ) trend originating in November 2021 prompted ODI to open PE22002. VOQ narratives reported unexpected brake activation while using TACC, Autopilot or FSD. The trend grew from 99 by the end of 2021 to 314 by February 16, 2022, when PE22002 was opened. ODI sent Information Request (IR) Letters to Tesla on May 4, 2022, and July 11, 2024, to request salien

When it happens

The middle half of failures fell between 2,000 and 14,169 miles, from the 16 reports that gave a mileage.

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What owners wrote

“Phantom braking events on most every type of road and drive when using cruise control, not autopilot or other automated systems. Standard cruise control is unusable and is a safety concern with constant warning alerts and automatic emergency braking when other vehicles pass by safely in the adjacent lane.”

Filed Dec 17, 2021

“Driving normally, with cruise control (not auto steering) engaged vehicle will spontaneously and dangerously apply emergency breaking. This happens regularly to the point I won’t use it. It’s going to cause accidents, especially when slippery conditions exist.”

Filed Nov 29, 2021

“Vehicle will randomly have phantom braking and braking events when using adaptive cruise control. It happens more often when a vehicle has recently passed and it 150+ feet in front of the vehicle. This poses a safety risk for vehicles behind as the car will randomly slow down. The adaptive function becomes unusable.”

Filed Nov 28, 2021

“Whenever TACC (cruise control) is engaged and the car is on a two lane highway with no divider, it will aggressively brake and trigger the collision warning system when a semi-truck passes going the opposite direction.”

Filed Nov 22, 2021

Should you keep driving it?

This page can't tell you that. 3 of 261 reports involved a crash and 3 people were hurt. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.

File your own report with NHTSA. Complaint counts are how a problem gets an investigation.

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