Accelerate/Brake Yo-yo

[ChaseMe]

I’ve had a great experience with autopilot on highways for over a year now. Was really happy when hard braking for overpasses became a thing of the past (mostly). Totally love auto navigate.

However, I was on a highway yesterday, with a very light traffic pattern, and no one in my lane for 20 car lengths, and I engage autopilot. I had the AP set to 75 as I usually do, and the traffic flow was about that.

Autopilot began to gently brake until I was down to 63mph. Then it would gradually accelerate to 73. Then it would brake to 63, and it would repeat. I drove for a mile this way, and experienced about 5 cycles of this behavior. Rebooted the system while driving, no difference. Parked for a couple hours and hit the highway again, no difference. Adjusted my follow distance from 2 - 7 - 2, no difference. No cars in front of me. Cameras appear to be clean.

First time running AP after the last update.

Running 2019.12.1.1 4b1dd29 on a HW2 Model S

 

[bishoppeak]

I've noticed the same behavior. I'd guess all the bad press made the safety guys gunshy and they made autobraking more sensitive.

 

[ChaseMe]

I've noticed the same behavior. I'd guess all the bad press made the safety guys gunshy and they made autobraking more sensitive.

No, that’s not it. There is nothing but pavement in front of me. Ping pong between 10 mph every 10 seconds. It’s unusable as is. I’ll take it in for service and report what they say.

 

[bwilson4web]

However, I was on a highway yesterday, with a very light traffic pattern, and no one in my lane for 20 car lengths, and I engage autopilot. I had the AP set to 75 as I usually do, and the traffic flow was about that.

Could you identify the segment, say Google Map or Google Earth links? The reason is I would be interested in repeating the symptom.

Better still, a video showing what happens.

Bob Wilson

 

[Blue5]

I have experienced the same problem. On AP the car slows down by itself without any cars in front of it, then accelerates, then randomly slows down. I’ve been experiencing it for 2 weeks in random parts of Southern California. Resetting the car made no difference. I’m taking it in for service but the next available appt is over a month from now. Prior to this I had the lane line side to side ping pong behavior on AP for several months; now I have forward-backward yo-yo dynamics. My family is scared to ride in my car. I have a ‘17 MS 75 with AP2 and FSD. Software 2019.12.1.1 4b1dd29.

 

[Saxgod]

Afraid to ride in the car? Wouldn’t not using autopilot keep your family from being terrified?

 

[D-D-L]

No, that’s not it. There is nothing but pavement in front of me. Ping pong between 10 mph every 10 seconds. It’s unusable as is. I’ll take it in for service and report what they say.

ChaseMe: Please let us know what Tesla Service says. I am experiencing the same thing in my Model 3 for the past couple of weeks.