2021 Tesla Model 3: adaptive cruise control problems

Filed Oct 4, 2026 · Brakes, Driver assistance · NC

Urgent Safety Concern — Uncommanded Braking During Manual Driving. On October 2, 2026, while driving my 2021 Tesla Model 3 Standard Range manually at approximately 45 mph and slowing to make a turn at an intersection, my vehicle unexpectedly applied very strong braking for approximately 1–2 seconds before releasing. Neither Autopilot, FSD, nor Traffic-Aware Cruise Control was engaged. I am concerned about a possible unintended Automatic Emergency Braking activation or braking-system malfunction. This creates a serious safety concern for my family, including our newborn child. I request that this be urgently reviewed and determine what triggered the braking, including whether AEB, ABS, or another braking-control system intervened in suck similar cases, so many were reported online. Please also provide the diagnostic findings and a written assessment of whether the vehicle is safe to operate.

Filed Sep 10, 2026 · Driver assistance · PA

Interior camera circuit failed in the main computer as diagnosed by Tesla, it disables most safety features of the car, no collision warning or avoidance, no automatic emergency breaking, no lane departure warning or correction, no reverse cam, no cruise control or self driving, and probably more. Only Tesla can replace it because it's vin matched to the car, for $2400. This part should be more durable

Filed Aug 3, 2026 · Driver assistance · UT

The adaptive cruise control on Tesla vehicles is dangerous. The model in question is a 2021 Model 3 but its an issue with many model years. The cruise control tends to get confused and applies the brakes during normal driving leading to very unsafe conditions for the Tesla and anybody behind it. The issue can happen in any environment and from 1-2 times per drive. There are no warnings or indications that the car is about to apply the brakes. The car has not been inspected by a service center but is in good working condition.

Filed May 11, 2026 · Acceleration, Driver assistance · UT

When using cruise control, there has been 4 times that the car has engaged in “phantom braking”. We were driving on highways going the posted speed limit of 70 mph, when the car suddenly slammed on the brakes and decelerated to less than 30 mph – all four times we were thankfully not being closely followed by another vehicle or we would’ve had a devastating crash. One time when we looked at the screen, it showed the outline of a person in the median but there was no person/ other obstacle at all. We have reported this to the Tesla service center and they said it is a known issue, and what we have to do is just click the scroll bar and report it so that the engineers can mark the timestamp and collect data so that some patches can be sent over the air/ uploaded at a future date. Nothing has been done to fix the issue and we feel dismissed about our concerns about our family’s safety, and the safety of drivers around us.

Filed Apr 20, 2026 · Driver assistance · IN

When using the cruise control or self driving function the car will, unprovoked, brake suddenly and severely. Hitting the acceleration pedal will disengage the cruise control or self driving and will stop the deceleration. The error happens about 1-2 times per 20 miles. I do not use these features often due to several near miss car crashes due to deceleration error. Sometimes the car will report other phantom alerts (like curvature assist on a straight road).

Filed Apr 17, 2026 · Acceleration, Driver assistance · CA

2 problems 1,Phantom braking when cruise control is activated. 2, There's no rear door mechanical release in the event of a electrical power failure in the event of R.T.A

Filed Dec 19, 2025 · Visibility · OR

-- Summarized Explanation The automatic windshield wiper system behaves unpredictably and creates unsafe driving conditions. Wipers frequently activate when there is no rain, operate at excessive speeds during light rain, and, most critically, fail to activate during active rainfall. These failures reduce driver visibility and increase the risk of a motor vehicle crash. Automatic wipers are forcibly enabled whenever cruise control or Autopilot is activated, regardless of weather conditions. This requires the driver to repeatedly adjust or disable the wipers while driving. Sudden transitions to maximum speed during light rain are distracting and divert attention from the roadway, increasing cognitive load during vehicle operation. -- Attempted Remedies •Replaced windshield wipers multiple times using different manufacturers •Cleaned forward-facing camera/rain detection area •Applied windshield water-repellent treatments •Installed approximately 30–50 over-the-air software updates over four years •Multiple inspections at Tesla-authorized service centers Tesla has consistently stated the system is operating “as intended,” despite continued unsafe behavior. -- Additional Notes There is no option to permanently disable automatic wipers when cruise control or Autopilot is enabled, nor any way to adjust sensitivity of the rain detection. Because the system repeatedly re-enables itself, the driver must divert attention from driving to manage wiper behavior, often multiple times during a single trip. This is especially hazardous when using standard cruise control without Autopilot, where full driver attention is required.

Filed Dec 1, 2025 · Driver assistance · NC

The car, with no known or evident driver, stopped the lane awareness, cruise control, etc. All of those just stopped working and per Tesla that's expected which is surprising since it's all part of the safety systems. The car's visual cues stopped identifying lanes and as a byproduct of that, none of the dependent features work.

Filed Aug 18, 2025 · Driver assistance · CA · crash

Component/System involved: Advanced Driver Assistance Systems — FSD (Supervised)/Autosteer (Lane Keeping Assistance) and Adaptive Cruise Control. Possible failure to warn/stop (FCW/AEB). Vehicle and data are available for inspection upon request. I preserved dashcam files and requested Tesla to preserve engineering logs and EDR. What happened & safety risk: On [XXX] at ~[XXX] PDT on [XXX] near East Palo Alto, CA, with FSD (Supervised) engaged, the system appeared to misinterpret an exit ramp/gore area as a continuing lane at a highway fork and maintained ~60 mph (posted ~70). As soon as I saw the trajectory was unsafe, I braked and began manual steering takeover, but the vehicle contacted a roadside sign near the gore/shoulder before I could complete the maneuver. I then stopped safely. No other vehicles were struck. Airbags did not deploy. This posed a serious collision risk to me, my passenger, and nearby traffic. Reproduction/confirmation: NOT REPRODUCED. I have not attempted to reproduce the event. UNKNOWN whether the issue has been reproduced by Tesla or a service center yet. Inspection to date: Police responded (report pending). My insurer has opened a claim. I opened a Tesla Service request asking to PRESERVE Autopilot/FSD engineering logs for the incident window and to coordinate EDR extraction; engineering review pending. Vehicle remains drivable. Warnings or symptoms before failure: No audible/visual forward-collision warning was perceived by me and I did not observe automatic emergency braking. No prior warning lamps/messages were noticed before the departure toward the gore. UNKNOWN whether any internal/partial interventions were recorded in logs. Evidence available: Four-camera Tesla dashcam footage saved and backed up (see [XXX] ); precise time window ~[XXX] PDT on [XXX]. I can provide files and cooperate with data retrieval/inspection upon request. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 8, 2025 · Driver assistance · CA

While using traffic aware cruise control or autosteer, the car occasionally detects a nonexistent person in the center of the lane I’m driving in, the proceeds to slam on the brakes when no hazard exists. It seems that tire markings in the road and certain lighting conditions cause the car to think there is a person in the road. Additionally, when driving on a highway with rolling hills, the car detects a forward collision alert and hits the brakes and disengages the autosteer. Both of these could cause a rear and collision at highway speeds. The dealer has claimed that the cause is functionally normally and I already tried to get it serviced but the car continues to have these issues. I do have video evidence of the car slamming on the brakes and detecting a forward collision.

Filed Jan 14, 2025 · Driver assistance · MA

I was driving east on [XXX] in Bourne MA using the Tesla adaptive cruise control system called "Autopilot" in very light traffic conditions. The sun was low on in the sky (behind and to the right). The system automatically engaged the brakes while crossing the bridge without obvious reason, decreasing the car speed about 10 MPH in less than a second before I overrode by pressing the accelerator. I believe the car vision system mistook a shadow cast by the vertical girders on the bridge onto the road as an obstacle. The sudden deceleration was a hazard to those behind that had to brake, but there was no collision or loss of control. The manufacturer seems acknowledge and accept that the defect exists, but has not been able to resolve the problem. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Dec 1, 2024 · Acceleration, Brakes · CO

vehicle constantly phantom brakes while driving. i have reported 100+ incidents thru my tesla "report bug" feature. It will read the speed limit sign on the off ramp and slow the vehicle down 20mps abruptly, it will see a car on an onramp and slam the brakes on thinking there is a collision coming. it is every single day using cruise control