The contact owns a 2021 Tesla Model S. The contact stated that while driving at various speeds with the cruise control feature engaged, the brakes independently activated without the brake pedal being depressed. No warning light was illuminated. The local dealer was contacted; however, the vehicle was not diagnosed or repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 65,000.
2021 Tesla Model S: adaptive cruise control problems
15 of the 179 complaints about the 2021 Tesla Model S describe adaptive cruise control problems.
- owner complaints
- 15
- of this car's complaints
- 8%
- recalls
- 4
Is there a fix? There are 4 recalls and 2 service bulletins for this area of the car. See below
Adaptive cruise control problems by model year
What owners say
Driving Southeast on [XXX] between Gallup, NM and Albuquerque, NM. I was traveling at 75 MPH on an open road, it was a sunny day. I had the adaptive cruise control engaged (ACC). Literally no traffic in front of me for as far as the eye can see. Nothing that would cause an alert or obstruction in front of the car. The Tesla was on ACC and suddenly braked, hard. I immediately disengaged the ACC and drove manually. It was a frightening incident. If there had been traffic behind me, it would have resulted in a crash, as I would have been rear ended. If the traffic had been a truck behind us, we would probably have sustained extreme injuries. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
The horn is a button. As someone almost steered into me, I looked down to find the horn and almost ran into a child as my car swerved!!! This is incredibly unsafe to hide the horn button in an incredibly small area next to the wiper button and cruise control. How this was approved is beyond me!! Tesla needs to make all current cars correct by having the horn be accesible. Like every other car in the world!
Vehicle braked without warning with cruise control engaged. Luckily there were no other vehicles near us when this phantom braking occurred.
The adaptive cruise control has had phantom braking issues from day 1 of ownership (and through every software release from Tesla as I always update when a new one is available). Most of the time it's not possible to identify exactly what triggers the event. However, on July 27th 2023 I drove from Phoenix to Sacramento via I10, I210, I5 and had 6 phantom braking events. 5 were directly correlated with passing a semi with me in the #1 lane and the semi in #2. I had the car in adaptive cruise control mode, but I maintained steering control. The car approached the semis normally, but as soon as the car was completely alongside the truck it began braking aggressively. More than just allowing regenerative braking to slow the car, the brakes were applied. This did not happen with every passed truck, maybe 1 in 10. One of the 6 phantom events could not be correlated with any clearly identifiable cause. There is no warning when the car begins decelerating so it is a surprise to the driver. Further it is an extreme hazard to following vehicles who WILL be forced to react. I have not directly reported my specific events to Tesla. For one thing they have no reasonable way to do this (online access, phone access. The number they give to report problems hits an automated phone tree where there is no option for reporting issues). Clearly Tesla is well aware of their phantom braking issues. I'm reporting this to you now in order to apply more pressure to Tesla to finally resolve this. In general, considering some of the other phantom braking episode beyond this one specific trip, I have occasionally noticed the car displays a yellow signal light on the driver's display but only while phantom braking has already begun. I believe this is case where the car believed it saw a caution sign or signal light in it's cameras and was reacting to that. There were no signal lights, but the sun was either coming in that direction or reflected off of other vehicles or buildings.
Adaptive Cruise Control. The vehicle in this mode suddenly brakes for no apparent reason which under the right circumstances could cause a collision. Tesla Service Center looked at it but could not reproduce. This has happened many times on various dates not just once. Sometimes it happens more than once on a trip, sometimes it does not happen. This happens with no warning. Tesla knows about this problem for years but has failed to correct.
When using adaptive cruise control vehicle randomly applies brakes while driving at highway speeds, for no reason. Sometimes braking is severe, sometimes moderate, sometimes light. In the instances of severe or moderate braking, a real danger exists that following vehicle will be unable to stop and will collide. This happens relatively frequently, particularly on some highways. Sometimes multiple incidents occur on one drive.
The Traffic-Aware Cruise Control has been braking unexpectedly and for no valid reason. The most recent example was when we were driving along US Hwy 24 between Wilkerson Pass and Fairplay, CO. The car suddenly braked even though there was no hazard. This has been happening regularly on this drive, in both directions, multiple times per drive. When this happens, the road is generally straight, with little, if any, elevation change. This is a safety issue because if this happens when a car is driving closely behind us, the unexpected braking could result in a rear-end collision. I have not reported this to Tesla because I understand this is a widespread issue that many people encounter, so I believe Tesla is fully aware of the issue. This problem seems to have gotten significantly worse after Tesla deactivated RADAR in the vehicle (without my consent). My understanding is that they are now using only cameras to manage Traffic Aware Cruise Control. Regardless of the reason, this issue has been happening with much greater frequency since around December, 2022 or January, 2023.
Today was at least the 3rd time "phantom braking" has occurred. While traveling on I-64 in Virginia, my speed was about 75mph with adaptive cruise control on. Suddenly, the car braked hard, slowing to about 40mph. I thought the car was going to stop. Fortunately, there were no vehicles behind me or there could have been a rear end collision. I did not use the automatic feature again for the rest of that drive.
Car repeatedly, randomly slams in brakes while cruise control engaged for no apparent reason. Not speeding, no other cars or blockages around, open highway on a bright, clear day.
The vehicle intermittently brakes for no reason with the cruise control enabled. This is going to cause an accident.
The vehicle put the brakes on when on adaptive cruise, but with very few cars around. The last time, there was no car in front of me, but the vehicle braked so fast the the car behind me almost rear ended me. I’ve noticed that it happened twice on a South bound stretch of I-35 in Temple texas. This needs to be addressed or there is a strong potential for an accident.
Service bulletins that may apply
Related recalls
Back over prevention: software
- What is wrong
- Tesla, Inc. (Tesla) is recalling certain 2017, 2021-2023 Model 3, 2020-2023 Model Y, 2021-2023 Model S, and Model X vehicles operating software version 2026.8.6. The rearview camera image may be delayed when the vehicle is placed in reverse. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
- Risk
- A delayed rearview image reduces the driver's view behind the vehicle, increasing the risk of a crash.
- Remedy
- Tesla has released an over-the-air (OTA) software update, free of charge. Owner notification letters were mailed July 3, 2026. Owners may contact Tesla customer service at 1‑877‑798‑3752. Tesla's number for this recall is SB-26-00-001.
Recall number 26V283000 · Recall details
Forward collision avoidance: warnings: external/pedestrian alert
- What is wrong
- 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
- 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.
Recall number 24V153000 · Recall details
Forward collision avoidance: warnings: external/pedestrian alert
- What is wrong
- Tesla, Inc. (Tesla) is recalling certain 2020-2022 Model S, Model X, Model Y, and 2017-2022 Model 3 vehicles. The Boombox function allows sounds to be played through an external speaker while the vehicle is in motion, which may obscure 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
- Pedestrians may be unaware of an approaching vehicle if the PWS sounds are obscured, increasing the risk of a crash.
- Remedy
- Tesla will perform an over-the-air (OTA) software update that will disable the Boombox functionality when the vehicle is in Drive, Neutral and Reverse modes, free of charge. Owner notification letters are expected to be mailed April 5, 2022. Owners may contact Tesla customer service at 1‑877‑798‑3752. Tesla's number for this recall is SB-22-00-003. Note: This recall has been superseded by Recall 22V‑235. Tesla's number for the new recall is SB-22-00-003.
Recall number 22V063000 · Recall details
Forward collision avoidance: sensing system: camera
- What is wrong
- 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
- 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.
Recall number 21V846000 · Recall details
Questions about the 2021 Tesla Model S adaptive cruise
Is adaptive cruise control problems a common problem on the 2021 Tesla Model S?
15 of 179 owner complaints about the 2021 Tesla Model S (8%) mention adaptive cruise control problems. The model year with the most reports is 2017.
Is there a recall or service bulletin for this on the 2021 Tesla Model S?
There are 4 recalls and 2 service bulletins for the same area of the car. Check them below with your VIN.
Other symptoms on the 2021 Tesla Model S
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