2021 Tesla Model Y: adaptive cruise control problems

Filed Sep 16, 2026 · Driver assistance · TX

The Tesla will randomly when the Adaptive Cruise Control is engaged brake from highway speeds down to 30mph. This happens when you go by off ramps and at some intersections on the highway. 1) At the intersection of [XXX] and [XXX] in [XXX] it happens sometimes especially if there is a vehicle next to you 2) At the intersection of [XXX] and [XXX] 3) Off ramp on [XXX] and [XXX]. these are the places that it happens the most. It does very randomly do it at other locations. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 15, 2026 · Driver assistance, Electrical · WA

On or about XXX my Tesla Model Y downloaded FSD version 14 Lite. One day after downloading the software, I used FSD and the new software caused the computer to overheat. This killed the car computer and made FSD, adaptive, cruise control, lane keep assist, reverse camera, and many other functions, including GPS and navigation inoperable. My car’s warranty expired in January of this year and Tesla will not cover the replacement car computer. There are hundreds of other complaints of this issue reported online on [XXX], Reddit, Facebook, etc. In the 2nd quarter Tesla Earnings Call, [XXX] declared that hardware 3 equipped Tesla vehicles would not be able to support autonomous driving with full self driving. He stated every hardware 3 vehicle will need to be updated with a hardware 4 computer and cameras. Since my hardware 3 computer failed, I requested the hardware 4 computer and cameras to be installed, but Tesla denied this service even though [XXX] said it was a requirement. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 25, 2026 · Acceleration, Driver assistance · CA

I own a 2021 Tesla Model Y with an HW3 car computer. At approximately 54,000 miles, the vehicle developed intermittent failures of the cameras, GPS/navigation, and cruise control. On two occasions during the same routine drive, about 40 minutes into the trip, the GPS, cameras, and cruise control abruptly stopped functioning at approximately the same location. The first occurrence was about July 7, 2026 at 9:15 AM and the second August 7, 2026 at about 3:15 PM. I made the same trip once between these events without a failure. I had also previously experienced a frightening incident while driving northbound on I-280 approaching the lane division for 19th Avenue in San Francisco using Autopilot. Where my lane widened and a new lane began, the vehicle abruptly attempted to follow the new lane to the right. I had to intervene firmly with the steering wheel to maintain control. I do not know whether this event was related to the later diagnosed computer failure, but report it because of its possible safety significance. Tesla serviced the vehicle in Sunnyvale on August 16, 2026 at 54,565 miles. Tesla's invoice states: “Technician addressed the intermittent loss of GPS, cameras, and cruise control. The car computer had board-side failures and was replaced.” Tesla replaced the HW3 computer with a Hardware 3.2 computer, part 1775000-S0-L. Tesla also found corrosion at the 12V input and replaced the 12V battery. My concern is that the HW3 computer failure was intermittent and simultaneously affected cameras, GPS/navigation, and cruise control. The vehicle operated normally between failures, so a driver could not know when the problem might recur. I ask the federal safety agency to determine whether similar HW3 computer failures are occurring in other 2021 Model Y vehicles.

Filed Jul 6, 2026 · Driver assistance · TN

Safety features on vehicle stopped working after software update was pushed to my vehicle. GPS, all cameras including backup camera and ones used for blind spots, and cruise control have all stopped working. Time displays incorrectly due to GPS issue and night mode stays on so rear view & back window stay dark making it hard to see other vehicles around me during the day. I’ve followed all recommended steps to resolve and issue persists.

Filed May 8, 2026 · Driver assistance, Electrical · CA

My 2021 Tesla Model Y HW3 experienced complete failure of all cameras, GPS, Automatic Emergency Braking, and Adaptive Cruise Control following the installation of software update 2026.8.6.1 — the OTA remedy update issued by Tesla for the federal safety agency Recall 26V283000. The vehicle was fully functional prior to this update. The failure was confirmed and reproduced by Tesla's authorized service center. The service advisor confirmed in writing: "During the update, the computer failed to reboot properly. We attempted to perform a 12V reset but unfortunately it is still stuck in the boot loop state." The Autopilot ECU (Primary/Turbo A) is stuck in a permanent boot loop and cannot be recovered by software means. Safety impact: All cameras including rearview camera are completely non-functional. Automatic Emergency Braking and all ADAS features are disabled. The vehicle cannot safely detect obstacles or pedestrians. GPS navigation is frozen. Tesla has confirmed the computer requires replacement but is classifying it as a customer-pay repair citing expired warranty, despite the failure occurring during Tesla's own recall remedy software deployment. This vehicle meets every technical criterion of Recall 26V283000 — HW3 hardware, 2021 Model Y, software version 2026.8.6.1, complete camera failure — but does not appear in the recall VIN database. I am requesting the federal safety agency review whether this VIN should be included in recall 26V283000 or a related investigation.

Filed May 7, 2026 · Acceleration, Driver assistance · MI

The vehicle began experiencing repeated Autopilot/FSD failures while driving. Symptoms included sudden Autopilot disengagements, cruise control becoming unavailable, and loss of road visualization/navigation display functionality. The issue progressively worsened over time. The vehicle was first brought to Tesla service in 2025 for the same overheating-related concern. At that time, Tesla identified a coolant-related issue, topped off the coolant system, and returned the vehicle to service. However, the problem continued and gradually became more frequent and severe afterward. During the most recent service visit, Tesla diagnosed the HW3 Autopilot computer as overheating due to a heat transfer failure between the Autopilot board and cooling cold plate. Tesla stated that heat generated by the board could no longer be efficiently transferred to the coolant system, causing the Autopilot computer to overheat. Tesla further advised that continued operation without repair could eventually impact additional vehicle functions, including the center display screen shutting off due to overheating-related failures. Given the loss of driver-assistance functionality and potential impact to core vehicle systems, I am submitting this report so the issue is documented as a potential thermal management or hardware reliability concern involving the HW3 Autopilot computer system.

Filed Feb 27, 2026 · Acceleration, Driver assistance · NY

Vehicle will suddenly apply brakes while using standard cruise control for no apparent reason. This is extremely dangerous as it has almost caused several accidents on the highway. I have almost been rear-ended several times. This is a very common problem and well documented problem referred to as "phantom braking" on Teslas and something needs to be done immediately.

Filed Feb 27, 2026 · Driver assistance · FL

The vehicle's Autopilot/Full Self-Driving (HW3) computer has failed at approximately 70,000 miles. Tesla Service has diagnosed the vehicle as requiring replacement of the HW3 computer. As a result of this failure, multiple safety related systems are inoperative, including collision avoidance, lane assist, lane departure warning, automatic wipers, and other driver assistance features including adaptive cruise control. The vehicle is also unable to receive over-the-air software updates, including potential safety updates. In addition, the vehicle experiences system lag, including delay when shifting into Drive or Reverse. The center display is slow to respond, and certain media and software features are no longer functional due to inability to update. This condition increases safety risk because active safety systems designed to assist with collision prevention are disabled. The failure appears to be hardware-related and not due to normal wear. Tesla has confirmed the need for computer replacement but has declined coverage as the vehicle is outside warranty. The failed component should be available for inspection upon request.

Filed Jan 27, 2026 · Brakes, Driver assistance · MN

When driving with cruise control engaged the car randomly brakes and shows a "curvature assist " indication. The car quickly slows from 55 to 35 with no warning. This primary happens on a straight road, not a curve. I am concerned about the traffic behind me.

Filed Nov 21, 2025 · Brakes, Driver assistance · MN

The car has a feature called "curvature assist" that takes control of braking and steering at times when using cruise control. The incidents are at times surprising as there is no curvature present but the braking is suddenly applied. This is a surprise for both the driver and any following traffic. The car would be safer if this feature could be disabled but that is not possible.

Filed Sep 16, 2025 · Driver assistance · AZ

Tesla’s Full Self-Driving (FSD) system has repeatedly demonstrated unsafe behavior in my 2021 Model Y (VIN [XXX] , ~60,184 miles). The issues involve Adaptive Cruise Control, Lane Keeping Assistance, and Forward Collision Warning. FSD frequently follows vehicles too closely, leaving insufficient distance. When I disengage, I am left with no safe option: braking hard risks being rear-ended and triggers a hard-braking event, while lifting off the accelerator leaves me dangerously close, still flagged as unsafe following. FSD often waits until less than a mile before highway exits to attempt lane changes, causing last-second darting, missed exits, or unsafe maneuvers. It also performs excessive and unnecessary lane changes that add risk without improving efficiency. Merges are frequently unsafe, forcing me to brake hard to let others pass or accelerate aggressively to avoid being cut off. On several occasions, FSD has jerked or swerved into adjacent lanes without signaling, seemingly triggered by shadows or changes in the road surface. These phantom maneuvers are unpredictable and hazardous. On [XXX] at about [XXX], at a T-shaped intersection, FSD failed to yield to a vehicle traveling straight with the right of way while I was making a left turn. I had to slam on the brakes to disengage, narrowly avoiding a collision. This was the second such incident in the same intersection in one week. These repeated failures—unsafe following, late exit attempts, failed merges, phantom swerves, and failure to yield—create significant risks for me, my passengers, and surrounding drivers. The problem has been reported to Tesla multiple times via in-car voice reports and a written service request, and logs from my vehicle should confirm these events. No warning lamps or system alerts appeared before or during the failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 27, 2025 · Driver assistance · CO

Immediately after an over-the-air (OTA) update on Aug 8, 2025, my vehicle began showing camera connection errors and disabled multiple safety/ADAS features. Over the following days, I repeatedly received alerts that AEB was unavailable. The vehicle remained drivable, but AEB and related safety functions were inactive. Chronology: Aug 8, 2025: OTA software update to 2025.26.6 completed. Right after completion, the touchscreen displayed camera connection errors and disabled AEB / Autopilot / cruise control. Aug 11, 2025: While driving, I again received an “AEB unavailable” alert. Similar alerts appeared intermittently throughout the week. There was no water intrusion, impact, or external damage. Cameras were clean and unobstructed. I scheduled the earliest available Tesla Service appointment and reported the AEB failure as a safety issue. Service diagnosis: Tesla diagnosed a failure of the Autopilot computer (HW3) and ordered a replacement. Cost/coverage: I requested that the repair be covered by Tesla because the failure started immediately after the OTA update and I am a paid Full Self-Driving (FSD) purchaser. My request was denied; I was charged ~$1,600 (slightly discounted) for the computer replacement. Safety risk description: The failure disabled AEB and other forward-collision mitigation features without an external cause, beginning minutes after the OTA update. I consider this a safety defect because an advertised crash-mitigation system became unavailable during normal use, increasing crash risk. The timing suggests a possible software–hardware interaction (software change triggering or revealing a hardware fault) that could affect other vehicles.