Adaptive Cruise Control problems of the 2021 Tesla Model 3 - part 1

Tesla full self driving software malfunctioned and turned into oncoming traffic lanes instead of crossing over to the correct opposite side of the roadway. This occurred after getting off a on ramp in ukiah, California around 2am Nov 15, 2025. This could have put others in serious danger if there were cars coming in the oncoming lanes heading in the different direction. The problem has not been reproduced by a dealer or other entity. Yet this has happened to other Tesla drivers as well using fsd as you are probably already aware. No inspection and it was sudden and unexpected.

Central computer (motherboard), cameras (front/rear/side), autopilot/auto steer system. Error code: aps_w132. Description of problem: on or around [xxx], Tesla pushed a mandatory over-the-air software update to my vehicle. Immediately after, multiple safety-critical systems failed: all cameras (including backup) became intermittent or non-functional, auto steer/autopilot stopped working, and the car emitted constant distracting beeping alerts due to a critical motherboard failure. This made driving hazardous—impaired visibility for parking/reversing, loss of collision avoidance features, and constant audio distractions that could lead to accidents. I had to drive in this unsafe condition for weeks while waiting for service. Tesla attempted a remote fix but it failed. I scheduled service on November 19 for December 3 (19-day delay). Diagnostics confirmed the update induced the hardware failure, a known issue reported by other 2021 Model 3 owners on forums like reddit (e. G. , software bricking motherboards post-update). Despite this, Tesla refused warranty/goodwill coverage, quoting $2,576. 83 for repairs. Service advisors josh and andy were unprofessional: josh was rude/condescending; andy was aggressive, sarcastic, and retaliatory. After I mentioned filing complaints with the az attorney general and news channel 3, andy threatened $100/day storage fees with an impossible deadline (called at 4 pm Friday, close at 5 pm, demanded pickup by morning, then noon). He closed my ticket without authorization, delaying fixes and forcing me to contact another location—prolonging my exposure to the unsafe vehicle. This defect poses serious safety risks: sudden loss of cameras/autopilot could cause crashes. Tesla's awareness (from prior reports) and poor handling (intimidation delaying repairs) exacerbates the danger. No crash/injury yet, but potential is high. Please investigate this update-induced failure as a widespread defect. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

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.

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 Aug 13, 2025 at ~9:30 am pdt on us-101 sb 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. . Read more...

My Tesla has full self driving supervised. When I use this feature, since about three updates ago, my car has started braking for no reason. It hasn’t happened on a freeway, but, but on secondary roads, it will brake and try to come to a stop. It seems to do this, when there is a shadow across the road, or when there is a puddle in or near the road. Sometimes it will brake for no reason at all. I I have come close to being hit from behind. I think this is a dangerous situation that needs to be looked into.

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).

My Tesla was operating in full-self-driving beta when it experienced a sudden uncontrolled accelration event. I was driving on [xxx] at approximatley [xxx] this morning. The road speed limit was 40 mph. The car display was correctly showing that the road speed limit was 40mph. The speed offset in the cars setting was limited to 5 mph max above the speed limit. While the car was driving it suddenly accelerated very hard from approximately 40 mph to over 60mph before I was able to stab the brake pedal and kick the car out of full self driving mode. There were no errors, warnings, or signs that anything was wrong with the car. I have also notified Tesla via the service request function in the Tesla app under the section for "software performance". Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Ever since Tesla rolled out an update for everyone to beta test fsd, the adaptive cruise control has been changing speeds when near interstate type exits and entrances. I've had it change from 75 down to 40 mph which is dangerous in traffic. This change in speed some times is just a drop to the next 5mph increment, such as from 73 to 70. Sometimes it is more from 73 to 65 at the same place/exit. It is not consistent. The only thing consistent is it's near exits even when not in an exit lane or nearest lane to the exit. This "feature" needs to be removed as it is unpredictable which makes it dangerous. . Read more...

This car, like many Teslas, is experiencing what has been come to be known as phantom braking. When in the autopilot or full self driving, this car will occasionally to frequently, depending on the day, suddenly break where it will decelerate from say 65 mph to 45 or 50 in a very short period of time. This can happen in very busy traffic conditions. It seems to happen when I'm going faster rather than slower. For example, I haven't experienced it so much on city street. It seems much more prominent on highways. This is an issue that has many youtube videos about. It has been reported by many Tesla owners as well as the media.

On March 31st, Tesla alerted me that I had been "granted a 30-day complimentary trial of full self-driving" capabilities. They didn't make it clear that the service was automatically enabled (vs. Allowing me to opt-in) and did not provide any information about how it operates. Because I have no interest in the service, I didn't click the "learn more" button in the email. Since the service was turned on, the car has unexpectedly "grabbed" my steering wheel twice while I was driving. I now understand that it's possible that I turned it on without knowing it but, again, I wasn't given any instructions. I was terrified. When I pulled over and tried to find an "off" button, I discovered there is none. When I spoke to Tesla today, I was told that there is no "off" for the service and that all I can do set it to the least invasive setting and "live with it" until the trial period expires on April 30th. I can still feel the car self-adjusting my speed and steering. I remain terrified that it's going to cause an accident. The bottom line: because I've had the car for two years and did not purchase autopilot, I know there's a way to disable it entirely. Tesla is simply refusing to do it and using me as a lab rat with no regard for my safety.

When using cruise control, auto lane assist and auto pilot, the vehicle will brake or slow down without apparent reason. This can happen suddenly and dramatically. This can happen when there are other cars nearby, but also when there is no other traffic on the road. It is distressing enough when there are no other cars nearby, but can be a hazard when there is other traffic behind me and they have no warning this is happening.

Autonomous driving problem April 3, 2024 -5:00pm-6:00pm driving from cornelia, GA to commerce, GA on us-441 south at 60 mph driving on the right lane with very lite traffic. 6 different times the fsd (full self driving) (supervised) 2021 Tesla Model 3 starts signaling left and changes lanes with no traffic or vehicles in front. The 5th time fsd (supervised) changed lane to the left was a near car accident because a car was speeding at 70-80 mph from the rear and the vehicle changed lanes in front of the speeding car nearly causing an accident. The autonomous cabin driver detection sensor does continuously give false positive warning messages to the driver to "pay attention to the road" when I am wearing my glasses, so I have to drive without my glasses.

Hi Tesla installed a new software update yesterday. Today when I began driving my car and I turned on the adaptive cruise control I found that the car was completely in autopilot and it was extremely to take control over the car again as I was initially unable to steer and it took a few seconds for it to discontinue the autopilot. This is very concerning because the car was set in the preferences (see attached photo) to autopilot (full self-driving (supervised)" in the preferences) even though I have never used it and has it set to adaptive cruise control ("traffic-aware cruise control" in the preferences). I am concerned that Tesla switched the preference to autopilot just after offering a free 30 day trial which I did not accept. I understand that full self-driving has never been approved and yet Tesla is flaunting the law and forcing drivers to use it without notifying us or requesting our permission. Tesla needs to be immediately held accountable for this wreckless and dangerous behavior which put myself and likely many other driver's lives at risk. Thank you, robert ovetz, ph. D. 4156021585 rfovetz@riseup. Net.

On or around March 31, 2024 Tesla delivered a software update to my vehicle that changed the way adaptive cruise control is engaged, as well as the behavior of the vehicle when the setting is activated. In the few days since the change, I twice inadvertently engaged the adaptive cruise control, once while attempting to park on a congested residential street where it was very dangerous to have the vehicle accelerate without my taking action. I panicked and was able to shut it off quickly, but I didn’t know why it had been enabled. Today I was driving and had intentionally engaged the adaptive cruise control when the car attempted to signal and change lanes. This was wholly unexpected, and I was not prepared to monitor the vehicle taking other actions besides maintaining its lane and speed in traffic. I reviewed the settings for the feature and discovered the adaptive cruise control with lane guidance, termed “autosteer” in the Tesla vehicle, had been replaced by “self-driving (supervised). ” the activation of the feature was changed from a double pull on the shift lever to a single pull. This explained my twice inadvertently activating the feature, and the car propelling itself forward unexpectedly, on those two other occasions. It is extremely dangerous for the car manufacturer to suddenly and without warning change the way the vehicle is operated. I believe I was fortunate to avoid an accident on two occasions while the vehicle unexpectedly took control over driving. Had I not reacted within one second to disable the feature, I might not have avoided a collision.

After a recent update to the "full self-driving" software stack (new version2023. 44. 30. 25; fsd beta v12. 3), we drove from charleston to atlanta and back, with much of the trip on interstate highways 26 and 20. A very troubling new phenomenon was noted: every time we passed a "minimal speed" sign, the car would drop the speed limit setting on the control panel to 40 mph. In many of the iterations of this problem, the speed of the car dropped precipitously, creating a potentially dangerous situation. I had the software set to auto speed limit offset, which in some circumstances maintained the speed around 70 mph because it was keying on surrounding traffic, but in some instances the speed did not reset until we passed another "speed limit 70 mph" sign. Often, I had to react by manually raising the max speed setting to the speed limit. This happened repeatedly (essentially every time we passed a minimum speed sign, unless the sign was obstructed from camera view by a semi). Please address this with Tesla and ask for an immediate bug fix and recall (software update). It is potentially very dangerous.

My vehicle is 3 years old and has roughly 52000 on it. After a recent software update (within the past month or so) all of the automatic safety features such as automatic braking, blind spot monitoring, cruise control stopped working on the vehicle. I brought it to Tesla and they confirmed the issue and said the entire ecu needs to be replaced, a $2700 expense on a 3 year old car. There is a warning message every time I start the car that says the automatic breaking is not working.

While traveling west on i90 in dane county just before exit 147, I experienced unexpected braking while using tacc. My cruise speed was set at 72 mph and I observed the set speed changed itself to (I think) 40 mph. This caused the car to quicky begin braking to slow my speed to this new speed. I had to intervene and accelerate manually while also trying to reset the set speed. Thankfully no one was directly behind me, as this was incredibly unsafe. This has occurred at this location more than once. I'm not sure if the gps perhaps thought I was on the exit ramp instead? tacc and autopilot seem to work normally elsewhere. It has not otherwise been inspected.

You guys have ruined auto pilot and made it less safe. Quit trying to get a promotion or recognition by going after Tesla. My Model 3 was the safest car to drive hands down. I've had 17 different cars in the last 20 years, Tesla's are like anything else I've ever driven. The problem you caused by forcing stricter safety for autopilot, actually makes it way less safe. Before it assisted on highways so I could briefly do things like change temperature, music, or navigation without accidently running off the road or colliding with another vehicle. Now it's so sensitive with warnings to pay attention, it's actually a distraction. Look at my speed, warning to pay attention. Check my surroundings in mirror, warning. Change temperature, warning. It's too the point where it's distracting me more then anything I would do in a traditional car. Seriously, NHTSA can go fuck itself. Someone in the government always trying to make a name for themselves acting like a savior for the people. Why don't you make yourself useful and go after those shitty traditional company's like Ford. Ford always rolls out vehicles with serious safety defects, but weigh the cost of recalls/lawsuits against profit. Ford shouldn't be allowed to sell vehicles in the us, yet you go after Tesla, who in my opinion makes the safest car ever created.

The cruse control is unable to keep its speed and sometimes the vehicule breaks suddently on the highway, especially when the road is wet. The cameras are obstructed by mist or other dirt and the system does not work properly. Related to this problem, the wipers are dangerous to operate. When the cruse control is engaged, then the wipers are forced to automatic mode, which does not work properly. It could start to swipe the dirty mist and actually reduce visibility. Operating the wipers with the touch screen is a hazard, forcing the driver to leave the eyes from the road. I contacted Tesla about these problems last year and the company did nothing. Even worst, on their new cars they removed the stalks completely, which is a non sens. The NHTSA has to intervene.

Complete computer failure leaving cars safety systems not working. Had to pay 3000$ for a new computer for a new car. Did not have car for three weeks. No systems would work.

The latest software update version: 2023. 44. 30. 5. 1 08a3a7856854 is too stringent with having to keep eyes on the road that looking in the mirror causes it to beep. Also having to touch the steering wheel constantly is dangerous because if you move with slightly too much force, it disengages autopilot. I only use the autopilot feature on the freeway and I have never had an issue until this update, which I believe was made to make the system safer. In my view it is now much less safe since I’m not able to check my mirrors and ultimately I think it makes the autopilot feature useless. (I will not be using it) this is also less safe, in my view. Because before I would watch the road as the car steered, ready to take over, so it was like having redundant safety (human + machine). Now I’m back to just human safety.

After the latest update the Tesla autopilot feature is very unsafe to use. The screen constantly pings and nags the driver to pay attention drawing my attention away from the road. The system has become so sensitive that adjusting the ac down a degree causes the warning to pop up which distracts the driver and in my opinion is significantly less safe than the older version. The warnings are too sensitive and the noise/warnings flashing are significantly more distracting.

When autopilot is engaged, car unexpectedly brakes with no obstacle in front of car. Some called it “phantom braking”.

Problem: as the vehicle is driven and the adaptive cruise control, autosteer, fsd, …. Is activated. As the system detects an unexpected outside event, the vehicle would slow down for a few seconds, then it would continue driving and re-accelerate to about the same speed that it was before and/or to the maximum set speed. Opinion: this is can be dangerous if the driver is not observant, alert, and does not control the vehicle which can be dangerous and cause death, destruction, and/or damage to the driver, passengers, pedestrians, vehicle, surrounding vehicles, fixed objects, etc. Possible solution: as the vehicle is driven and the adaptive cruise control, autosteer, fsd, …. Is activated. Once the system detects an unexpected outside event the system should: * temporarily disable adaptive cruise control, autosteer, fsd, …. * interior cabin lcd would flash yellow/orange and beep quickly 3 times in a row - showing a message on the screen “for the safety of you and others _____ (adaptive cruise control, autosteer, fsd, …. ) has been temporarily disabled due to an unexpected outside event. Please re-enable ____ (adaptive cruise control, autosteer, fsd, …. ) when it is safe. ” possible solution reason: * temporarily disabling adaptive cruise control, autosteer, fsd, …. Disables the drivers dependence on the system, slows the vehicle, and forces the driver to take control of the vehicle, situation, and avoid the unexpected outside event. * alerting/notifying the driver alerts the driver to a dangerous unexpected outside event that the driver needs to assess and know the best course of action.

Fsd computer module (ap3 module) when starting to fail causes all active safety systems to top functioning, including but not limited to lane assistance, automatic emergency breaking, adaptive cruise control, lane departure warning, lane keeping assistance, blind spot warning, pre-collision systems, etc. This is due to the ecu that processes the video feeds from the cameras needed for these function begins to fail, and is not surprising. What is surprising is there are absolutely zero customer or service facing alerts for this issue. Customers simply are unable to manually activate some features, vehicle display has difficulty recognizing objects and lane markings, and the service menu (meant for vehicle service/repair) shows part of the ecu as critical in diagnostics, but does not provide an alert. I can only guess that as previously only half of the module was used at a time, with the second half being for redundancy incase of a failure on one part of the unit, still allowing for full functionality. However, in newer versions of the vehicles software both halfs of the module are used simultaneously to increase processing power, thus eliminating redundancy. It is possible that due to the past redundancy that a failure of one half of the unit was not considered a cause for alarm (though I would have hoped a failing component would have caused an alert, unless the companies hope was that one half would work long enough on its own until it no longer needed to be covered under warranty). However, given both processors and now being actively used there should definitely be alerts and warnings. In addition to losing the convenience of several of these systems there is also a negative safety aspect of systems such as accident avoidance, pre-collision seatbelt tensioning, and others may not work in a pending collision (not that I have seen these systems function properly in past collisions when the module was fully working).

While using adaptive cruise control, at highway speeds, there was aggressive, automatic braking when there was no vehicle in front of me. It happened about half a dozen times on a three-day trip from indiana to florida. Luckily, in each case there was no vehicle directly behind me.

The car's autopilot suddenly causes it to slow down without any apparent reason. There are no cars in front of me, and the speed limit hasn't changed. This unexpected deceleration is dangerous because the cars behind me may try to avoid me during the slowdown, which could lead to an accident.

Driver assisst function for cruise control/autosteer failed/malfunctioned. Applied emergency braking systems while autosteer/driver control active. Multiple times on freeway. Ota software updates require additional data downloading and are not required to install. Never received update and safety issues resolved via ota are already being exposed and they are not allowed to do anything to prevent any damage or loss to the vehicle. Wifi at all government ev charging stations is a basic requirement.

Driving on I-5 north from los angeles to san francisco with adaptive cruise control activated. Suddenly and without warning car activates emergency braking as if it sees an obstruction on the road but obviously road was clear of any obstructions. This happened 4 times then I finally decided to no longer use cruise control. This happened on a clear sunny day around noon time 9/8/23.

While the traffic-aware cruise control was engaged, my car abruptly tried to stop 8 times on the interstate while traveling at 80mph (the speed limit on the open stretch of road in central utah). The weather was clear, no clouds, no wind, very light traffic, very good roads, no debris on the road, about 85 degrees, no shadows were cast on the road and during the day. I was on a 5 hour road trip. Out of the blue on at least 5 of the occasions, with a vehicle about a half mile or more ahead of me and no vehicle next to me my car abruptly braked - like emergency breaking - for no apparent reason. Two of the phantom braking occurrences happened when after passing a vehicle and I signaled and pulled back in to the right lane with at least a 3 second space, and my car emergency braked. This about caused an accident and thankfully it did not cause a road rage incident. Two of the times we were snacking once on vegetables when the car phantom braked and the bowl and vegetables went flying forward. Thankfully none of the times did I have my cup to my mouth as I would have gotten hot coffee on me and could have burned myself or have caused some destruction to my car. The passenger in my car safety was at great risk as well as everyone on the road near me. No warning that the car saw something or was going to emergency brake. My vehicle is available for inspection. I have not taken it to a dealer or elsewhere for replication nor has the vehicle or component(s) been inspected. There were never any warning lamps, messages or other symptoms of the problem prior to the failure. Also, the problem occurs 100% of the time I am at one particular place on a local freeway so it can be replicated. I do know that it will occur there so I plan for it. When I travel this road south bound there is never a problem but when I travel north bound 100% of the time my car will phantom brake regardless if it's day, night, clear or wet. Tesla needs another option for cruise control now!.

Major phantom braking at 70mph on interstate 5, 4 times the brakes slamed on as if yo had done an emergency stop from 70mph to 20mph fortunately we were not rear ended as I had my son and grandchildren in the car. The car was in cruise control on each occurrence I finally had to stop using it for fear of a major accident.

My Tesla Model 3 phantom brakes when using cruise control, particularly in the morning when the road is clear, no cars or obstacles in front or behind me. The NHTSA knows this is a problem and I have previously made this complaint. I contacted Tesla to no avail. They did nothing. Why hasn't the NHTSA done anything about this issue. This is dangerous as an accident is waiting to happen.

I was driving west bound on i4 August 12th 2023 at 1236pm at mile marker 45-47. I was in the left hand lane with the cruise control set at 73 mph. All traffic was moving well. There was no car in front of me. There was a car passing me slowly on the right. There was a retaining wall to my left. My car for no reason changed the setting on my cruise control from 73 to 35mph. This caused my husband and I to be thrown forward and I had to jam on the gas to try to regain speed. This was the 4th time this happened and the second time I have reported to Tesla who insists that there is nothing wrong with the car. I am scared if someone is following me closely I will be rear-ended at a high rate of speed. They continue to quote information from the manual and in the invoices insinuating that any incident occurring from this would be my fault. This is a terrifying thing to happen when there is no reason for the car to slow for any reason.

While the car was parked in a parking lot, I get two notification stating “sentry mode has turned off due to a sentry system error. ” when I checked out the car, the car has completely failed to do any of the computer related task, leaving only the gear, ac, and bluetooth was working. None of the cameras, gps, sensors, brightness mode and many others were completely stuck. This continued until the next day. This happened without prior symptoms or warnings. I would have been in deep trouble if I have been driving at the time of the incident. When I took the car to the shop, Tesla didn’t update the status for a week. After a week, Tesla told us that the turbo a, autopilot main processor chip failed. This caused the autopilot to go on loop. Therefore the whole motherboard needed to be replaced. This happened to a brand new purchased Tesla 2021 standard range. Which cost me $2404. 00.

When cruise control is activated at highways speeds, vehicle sometimes brakes abruptly for no reason whatsoever. Issue is phantom braking. No other cars in sight, no changes in speed limits. Happened repeatedly on CA hwy 46 between interstate 5 and us 101 on 7/31/23 and 8/2/23. Similar instances observed on other highways, too.