Cruise control - a mind of it's own. Anyone else have this experience?

[Barry41561]

Good day - nice to join this forum. I have a 2020 S Long Range Plus = approx 4,500 miles.

So - when using the cruise control (not autopilot - although this occurs then too), the car will decide - on it own - to reduce or increase it's 'MAX' speed.

I now have a video of this - happy to share with anyone who wants to see it. On the Santa Monica Freeway, while traveling 65 MPH (my choice), the car suddenly reduced it's speed to 40 MPH MAX. There we no cars present - as it was extremely early. Fortunately, no one was behind me - so I did not get rear-ended. After restoring the car to 65 MPH, the car, just seconds later, upped the maximum speed to 79 MPH MAX.

This is incredibly dangerous -

Has anyone else seen this?

My local service person has seen the video - he's not sure there's anything that can be done.

Thought?

 

[DerbyDave]

More "phantom" braking. No other car manufacturer with much less cruise control systems has this issue. Only Tesla -- and next month they will be relying entirely on vision from the cameras and turn off the radar inputs, which is why the Tesla runs into trucks turned over across the road all the time. Please just do basic dynamic cruise control well first, Tesla. All other manufacturers have mastered this. Don't be last.

 

[Barry41561]

More "phantom" braking. No other car manufacturer with much less cruise control systems has this issue. Only Tesla -- and next month they will be relying entirely on vision from the cameras and turn off the radar inputs, which is why the Tesla runs into trucks turned over across the road all the time. Please just do basic dynamic cruise control well first, Tesla. All other manufacturers have mastered this. Don't be last.

I've experienced the 'phantom' braking - but - this isn't even that: This is the car with no traffic, or shadows, simply slowing / speeding up as it likes.

Crazy.

I have Tesla coming to see the car this week - we'll see what they have to say.

Has no one else experienced this?

 

[HAILERS]

I've seen this in Tx outside Ranger, Texas headed west up Ranger Hill. That stretch of hwy has been reconfigured in the last year and a half. When in cruise control the car drops from ??? 70-75 mph to well below 60 before I punch the accelerator and bring the speed back up. Going east on the same stretch of hwy,...no problems at all.

I think it has something to do with the reconfiguration of I-20 on that hill and only going west.

 

[Gwgan]

Is there a numbered road sign which could be confusing AP? I have one place where this happens all the time.
If the maps think this section of highway is a local road AP would reduce speed and show the target speed limit. I found the reverse with an overpass treated as a highway even though the road is local.

 

[Az_Rael]

Has no one else experienced this?

I have seen it on a section of the 5 near Burbank in the past. Speed limit goes from like 65 down to 25 or something. I think in that case the newly constructed road config in combo with a nearby surface street was the culprit.

Sometimes on my drive to work on a highway (not freeway) the camera misses a sign, so it will revert to 45mph after a few miles until I pass the next sign.

Overall, yes these types of bugs are fairly common. You eventually get a spidey sense for when the car is about to brake suddenly, but it will still surprise you occasionally. Keep your feet near the pedals when using TACC so you can react quickly if needed. If someone is tailgating, cover the pedal, or disable TACC.

It isn't a great situation, but it is part of the nature of the Tesla software ecosystem - they will probably make it better eventually, but maybe not before it gets worse first.

 

[brkaus]

It’s not “phantom braking” if it reduces the max speed.

its probably a map issue or the camera was confused by a sign. Perhaps in a side road?

 

[Silicon Desert]

Welcome. I haven't seen it, but my suggestion is that if you consider it incredibly dangerous, then stop using it until such time of a future update that you can try it again to see if it works the way you like.

 

[We Are Venom]

Good day - nice to join this forum. I have a 2020 S Long Range Plus = approx 4,500 miles.

So - when using the cruise control (not autopilot - although this occurs then too), the car will decide - on it own - to reduce or increase it's 'MAX' speed.

I now have a video of this - happy to share with anyone who wants to see it. On the Santa Monica Freeway, while traveling 65 MPH (my choice), the car suddenly reduced it's speed to 40 MPH MAX. There we no cars present - as it was extremely early. Fortunately, no one was behind me - so I did not get rear-ended. After restoring the car to 65 MPH, the car, just seconds later, upped the maximum speed to 79 MPH MAX.

This is incredibly dangerous -

Has anyone else seen this?

My local service person has seen the video - he's not sure there's anything that can be done.

Thought?

Have you had a new update before that happened? have you tried a full reboot of both ECU/MCU? best way to do this type of fresh reboot is temporary change the Wheel configuration to a different configuration then back to your true wheel configuration. that should clear both ECU/MCU

 

[jjanov79]

Unfortunately this is the consequence of the lag time between road construction and map updates. Maps/GPS thinks the car on a feeder/side street with a lower speed limit. Because new highways are typically much straighter than the old road it can cause the system to jump back and forth between highway and side street.

As much as I'd like to blame Tesla they're not at fault here. There is always a delay in maps updates and Tesla is at the mercy of a 3rd party. I know that speed limit recognition takes precedence so if the signs are posted properly, which is also a 3rd party, it should alleviate some of the issue. That being said I don't know if there is a time/distance expiration after it reads a speed limit sign before it reverts back to maps data.