2017 Tesla Model X: adaptive cruise control problems

Filed Feb 14, 2025 · Brakes · FL

Now I know it's called Phantom or Ghost Breaking. When in cruise control or in autopilot, in certain highway areas from 65 or 70, it breaks down to 25 mph. Cars behind gets dangerously close, as well as the royal scare face I get! There has been two major updates since I bought it, and it still does the same. Since, more or less, I know the highway spots where it happens, I'm ready for it. However, when traveling elsewhere I'm not that lucky. At those high speeds it cam potential cause harm or even death!

Filed May 5, 2024 · Acceleration, Driver assistance · CA

While driving CA-17, as is frequently the case, I had to disengage automatic steering several times to correct its poor lane keeping. Much to my surprise, the vehicle stopped maintaining speed, creating a dangerous situation with vehicles behind me as the uphill road caused the vehicle to rapidly decelerate the second I turned the wheel. After experimentation, I discovered that Tesla has completely removed cruise control capabilities from these vehicles unless you completely disable the FSD beta functionality, which makes this vehicle highly unsafe to drive in any environment where autosteer is inadequate, including CA-17. Further, this isn't just unsafe on weird highways. This poor decision on Tesla's part could very easily cause rear-end collisions on freeways. Nobody in their right minds would expect a vehicle to suddenly massively decelerate just because you correct its poor steering. This is just plain DANGEROUS. This so-called "Full Self Driving (Supervised)" version needs to be recalled immediately, and Tesla MUST be forced to make cruise control fallback available regardless of the FSD state. Until they do, it is fundamentally unsafe to allow Tesla vehicles to remain on public highways and freeways with FSD (Supervised) enabled.

Filed Sep 29, 2022 · Acceleration, Brakes · PA

Highly repeatable issue: driving on left lane of a highway going at high speed (60) with adaptive cruise control enabled (but *not* full self drive mode). Put on turn signal to merge into right lane. There was a car in the right lane directly next to me but I had not initiated the merge, was merely signaling my intent to merge. My car SLAMMED on the breaks (very dangerous as I was almost rear ended the first time by a 18 wheeler). Did some testing at a later date- if there is a car slightly ahead of me in the right lane, the car behaves normally (maintains speed) if there is a car in my blind spot, the car indicates there is someone in my blind spot but maintains speed. If I am driving in the left lane all three scenarios (slightly ahead, directly adjacent, in blind spot) the car maintains appropriate speed. It is only when car is directly adjacent when in left lane w/ right turn signal that car always now will slam on brakes. Very dangerous- Tesla has been made aware of the Issue 2x now- and had informed me that “it is beta software (?????!!!!!!) and to live with it.”

Filed Sep 9, 2022 · Driver assistance · OR

We were driving down the freeway in daytime sunny weather on “autopilot” (I was actively monitoring the vehicle of course) when the car SLAMMED on the brakes for no reason. It was aggressive and fortunately I disconnected the driver assist “autopilot” and immediately pressed on the accelerator (not an intuitive action) to avoid causing an accident. There was no reason for the car to behave this way. Furthermore, Tesla updated the software recently on my vehicle. I purchased the vehicle with radar, whereby it would use the radar as an input in coordination with other information for the adaptive cruise control and auto steer. (Collectively called the “autopilot” by Tesla. This recent software update took the radar out of the equation and made my car function differently (less robust) by now only using the cameras and not the radar. The cameras on my model year are not, to my understanding, of the same capability as the cameras that Tesla is using with their newest models. Despite the cameras being older, tesla modified the vehicle via over the air software update to only utilize the cameras, again, despite the car being designed to utilize the radar as an input to the semi autonomous driving. I take great issue with Tesla retroactively reducing the capability of my semi autonomous driving and not providing a warning or a clear choice. The phantom braking I experienced was after this software update that removed the radar. It’s one thing if a driver needs to be prepared to brake, but quite another if the car brakes EXTREMELY aggressively and the driver has to rush to press the accelerator, all while startled. I work as an airline pilot and this seeming total disregard for safety, removal of radar input that the car has on board already, and lack of transparency to the driver would never be accepted in aviation. I urge the federal safety agency to look into the aggressive uncommanded braking. Thank you, Stefan

Filed Jul 18, 2022 · Acceleration, Brakes · CO

The vehicle brakes are aggressively applied at random times when traveling on the freeway. This only appears to happen when the vehicles TACC (Traffic Aware Cruise Control) is enabled. Thankfully I have not been rear ended yet. My family's safety is in danger when TACC is enabled. Not only am I concerned we could be rear ended, but I am concerned someone could think I am "brake checking" them and then proceed to act violently (road rage). There is a particular stretch of highway where this happens 100% of the time that would allow me to reproduce the occurrence on demand for investigative purposes.

Filed Jun 21, 2022 · Brakes, Driver assistance · OR

Many instances of hard braking in cruise control with no cause. In the last 6 months it’s gotten very bad. It only happened very infrequently before when someone was turning off the freeway it would brake for just a second. Now it is braking hard in an extended fashion and multiple times in one trip. Sometimes we can see some reason, sometimes not. Once, traveling 75 MPH passing a large truck in the lane to my right, the brakes slammed on very hard. Fortunately, I had both hands on the wheel and avoiding crashing into him and the car be him me was far enough back to not hit me. Many other smaller instances, but today doing about 45-50 MPH the brakes slammed on HARD, didn’t release, and I had to steer to the left and hit the accelerator to avoid hitting a biker. I think the Tesla may have been reacting to the biker. I will not use cruise control any longer until it is fixed. It is terrifying and it’s just a matter of time until something really bad happens.

Filed Mar 19, 2022 · Acceleration, Driver assistance · WA

At 1:10 pm on Wednesday, November 10, 2021 we were travelling SB on I-5 near Longview, WA. The day was clear and dry. We were in Lane 2 of a 3-lane stretch of interstate. There were no vehicles in either lane right next to us; a semi-truck was in Lane 1 (outside lane) several car lengths in front of us; a passenger car was 1-2 car lengths behind us in the same lane as us (Lane 2). No overpasses, trees, or any other discernable distractions were present. We were travelling at 70 mph on cruise control. With no warning, the car braked suddenly in an effort to bring the car to a full stop. Fortunately, the driver directly behind us was paying attention and was able to swerve into Lane 3 to avoid rear-ending us. I was able to bring my car into the Tesla location in Lynnwood, WA for service on November 12, 2021 to have the issue checked. While in for service, I did some research on the issue and found blogs dating to 2018 about "phantom braking"; I determined this described our situation. When I collected the car, the service tech said they were unable to replicate the issue and therefore, were not able to establish a problem to correct. I inquired if they knew about a phantom braking issue; they indicated that Telsa had heard of it and was working on a "fix" but there was no known timeline for the "fix". I have not used the cruise control feature in my car since 11/10/21 and will not because of the significant safety concern. Tesla need to be MADE to make this safety issue a priority to correct. If Musk's team can build a rocket and send it to space, they certainly can correct a cruise control issue.

Filed Jul 12, 2021 · CT

The MCU screen (large touch screen in the center of dashboard) has been malfunctioning. This started a few months ago when screen seemed to "crash" -- as I'm driving, the screen will turn black and take a long time to come back. On other occasions the map won't load and I receive a notice for "network error" (and have 5g service and not a satellite problem.) This would happen on and off for the past few months. I reported it back in March and was told they would order parts and get back to me and haven't. Then the 12 volt battery died and they replaced it but the MCU problems didn't go away. The last time I drove it, the screen froze up, then turned black and didn't come back on. The collision warning, lane assistance, and adaptive cruise control and steering all stopped working. I COULD engage the auto pilot and cruise control (the notification showed on the small dash board on top of the steering wheel, that they were both engaged) however, they didn't work. I set the car to 65 on the highway and the cruise control wouldn't go over 50. Also, on the back roads, the car drove straight through stop signs without stopping.

Filed Aug 19, 2020 · Brakes · 75,000 miles · TX

The vehicle experienced a multiple-system failure. Warning lights indicated loss of steering assist, loss of cruise control, loss of braking assist, and other safety features. A reset of the computer rectified the issue, but only temporarily, and the software fails again and again. In failure mode, which comes on unpredictably, the brakes make a terrible grinding sound and are not as effective in stopping the car. This is a major safety concern. The onset of these failures is usually when the car is moving and occurs randomly.