2021 Tesla Model Y · symptom sheet
Adaptive cruise or lane keeping misbehaves
- 363owner reports
- 10,000median miles
- $3,500median quote
- 10involved a crash
Newest report Sep 16, 2026 · checked Oct 2, 2026
636 of the 1,079 complaints on this car are about collision avoidance. 363 of those describe driver assist, which makes it the most reported problem on the 2021 Model Y.
Tick what matches of 363 reports
Driver assist on other Model Y years
Report counts are for each model year on its own, so a newer car has had less time to collect them. Model years with too few reports of it for a sheet: 2025.
What this problem usually is
These reports come from drivers whose assistance systems did something they didn't ask for. Adaptive cruise switches itself off, or brakes for a car that isn't there. Lane keeping tugs the wheel toward the line, or a "sensor blocked" message appears on a clear day. Because both systems can brake or steer, owners tend to file them as safety complaints, and NHTSA files them under speed control, lane departure or forward collision.
What got replaced
Owners who name the part that was replaced mention the software (71 reports), the camera (32 reports) and the radar (24 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.
A factory reset muted the Pedestrian Warning System (PWS) sounds.
The fisheye and narrow camera cable terminals were incorrectly installed in the cable harness connector, resulting in swapped camera views.
A communication error may cause false forward-collision warning (FCW) or unexpected activation of the automatic emergency brake (AEB) system.
All 23 recalls on the 2021 Tesla Model Y, with the owner complaints on each recalled system
NHTSA investigations into collision avoidance on the Model Y
Sudden unintended acceleration. Open.
Unexpected brake activation. Closed jun 29, 2026.
What owners paid
6 of the 363 reports quote a price. Each dot is one quote. The middle half runs $1,600 to $5,770.
When it happens
The middle half of failures fell between 3,940 and 24,300 miles, from the 28 reports that gave a mileage.
What owners wrote
“When placed in cruise control (which is called TACC: traffic aware cruise control), and driving on 2 lanes road, the car frequently (more than 10 times over 20 miles) slams on the brakes when incoming large vehicles on the other lane. This is generating dangerous situation with following cars being surprised for sudden (and unwarranted) braking occurs. I have a dash cam video of one such incidents”
Filed Dec 1, 2021
“When driving on cruise control the car will suddenly and randomly decelerate and/or break for no reason. I have had this happen on empty two lane highways and on 4 lane highways with cars around me. It's incredibly stress full and if cars are following too close very dangerous.”
Filed Nov 29, 2021
“Driving I5N near Delmar with auto pilot in daylight, car suddenly braked while there was no obstacle, or any other car in front of it. Luckily no one rear-ended me. Max cruise speed was set to 75 MPH, and speed suddenly dropped below 45 MPH. The maximum cruise speed I set to also automatically changed to 45 MPH as well.”
Filed Nov 29, 2021
“Using basic Autopilot (adaptive cruise control without auto-steer), the car randomly slams on the brakes putting me at risk of being rear-ended by any vehicles following me.”
Filed Nov 19, 2021
Should you keep driving it?
This page can't tell you that. 10 of 363 reports involved a crash and 4 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. How reports land on this sheet.
Guide Paid for this repair before a recall covered it? How recall reimbursement works
Other problems on this car
- Brakes on its own (automatic emergency braking) 330 reports
- Brakes grind, pulse or wear early 181 reports
- Forward collision warning goes off or the camera drops out 104 reports
- Infotainment, screen or backup camera fails 103 reports
- Suspension noise, struts or alignment 75 reports
- Battery dies or the car will not start 52 reports
- Seat belt or seat problems 43 reports
- Full Self-Driving (FSD) does something unsafe 35 reports
- Power steering cuts out or goes heavy 30 reports
- Windshield cracks or distorts 26 reports