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Is my AP in SR+ trying to kill me

I have had the car now for over a month. I have tried TACC a couple of times and it seems to function decently. But it is not different from adaptive cruise on my Acura.

I have tried to engage AP twice and on both occasions it has led to near disasters. Both were activated while I was in the middle lane of an interstate going at 65 mph. The first time it started to veer to the right and almost swiped a car in the right lane before I hastily took over the control of the car.

The second time it started to accelerate to keep up with the speed limit of 70 ( had set 0 on my max limit). A gentle curve was coming up and instead of keeping up with the curve in the middle of my middle lane it started to cut across into the right lane. I had to steer hard to keep it in the middle lane or else I would have been run over by a 18 wheeler.

The first episode occurred with the V9.15... and the second one was yesterday after a V10 update. I am now afraid of trying out autopilot any more. I mentioned the quirks of AP to the SC a week ago when I took in for rattle and their comment was that it was "beta". I have no other Tesla to compare to know if this is normal behavior or there is something wrong with my car. The SC is 100+ miles away. Should I ask mobile tech to check it and see if this is normal behavior of my car compared to other Teslas. I heard so many good things about AP and arriving refreshed but then mine wants me to not arrive at all and instead give me heart attacks.
 
That certainly doesn’t sound normal to me, mine tracks lanes like it’s on rails. I’d suggest trying it out without traffic and seeing if it actually leaves it’s lane.

My car has 10,000 miles, and about 80% of that has been done on autopilot. Everything from interstate to ruralroads, and even some in town. It’s been fantastic for me, you might have something wrong with yours.
 
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^ What CharleyBC said. Based on your description, it almost sounds like you might not have AP engaged. The steering wheel icon will turn blue when AP is on. On TACC, it will be grey.

If all else fails, I would have your local service center verify the cameras are calibrated properly. You can likely get a service tech to do a ride-along with you. If your car can scare them sufficiently, trust me, they will fix it for you!

V10 has been great for AP. Easily the smoothest version I've experienced yet.
 
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Both my wife and I have M3 and it does have it's issues but what your experiencing sounds like sensor/HW issue possibly but I would think that the cars self diagnosis would catch stuff like that.

As others have said, make sure AP is really on. I know for sure myself have in past had it turn off with the chime but not register the chime until I realize it is drifting, and also I've manually taken it off and then couple mins later forgot only to be reminded on a curve, much like in your situation.

There is also the possibility that those two spots are anomalous for some reason, is a a regular commute for example and only happened those two times? I say as there a couple spots on my commute where it always behaves the same, either slowing to almost stop for some reason and trying to take left turn lane on a curve ?
 
I think the sales person kept the auto steer on when he demonstrated the car to us while we took delivery of the car. He stated that it will help in changing lanes in AP when you manually indicate with turn signal and gently assist.

I engaged the AP with the autosteer with the two downward clicks as described in the manual. The lane marking turns blue and there is blue circle around the max speed and the left upper T symbol turns blue.

I thought that even with autosteer on the AP should be the main driving mechanism unless I want to change lanes. So AP should work the same in my line with or without Autosteer.

In my second instance I had to turn the steering wheel hard to the left to prevent my car veering in the right lane that the action stopped the AP.

I will try one more time on a quiet road and if there are any issues I may have to get the mobile Tech to ride with me.
 
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mswlogo

Well-Known Member
Aug 27, 2018
8,362
7,883
MA, NH
I have had the car now for over a month. I have tried TACC a couple of times and it seems to function decently. But it is not different from adaptive cruise on my Acura.

I have tried to engage AP twice and on both occasions it has led to near disasters. Both were activated while I was in the middle lane of an interstate going at 65 mph. The first time it started to veer to the right and almost swiped a car in the right lane before I hastily took over the control of the car.

The second time it started to accelerate to keep up with the speed limit of 70 ( had set 0 on my max limit). A gentle curve was coming up and instead of keeping up with the curve in the middle of my middle lane it started to cut across into the right lane. I had to steer hard to keep it in the middle lane or else I would have been run over by a 18 wheeler.

The first episode occurred with the V9.15... and the second one was yesterday after a V10 update. I am now afraid of trying out autopilot any more. I mentioned the quirks of AP to the SC a week ago when I took in for rattle and their comment was that it was "beta". I have no other Tesla to compare to know if this is normal behavior or there is something wrong with my car. The SC is 100+ miles away. Should I ask mobile tech to check it and see if this is normal behavior of my car compared to other Teslas. I heard so many good things about AP and arriving refreshed but then mine wants me to not arrive at all and instead give me heart attacks.

Set the Speed Limit OFFSET to -20 and when you engage TACC it will use your CURRENT speed as your initial speed. This will also drastically reduce Phantom Braking.

AutoPilot will immediately seek out centering on the lane. Be sure you have good lane markings and you are in the center when engaging to avoid surprises. I've never had what you describe happen. But I can see how it can. I highly doubt your AutoPilot is broken, but it's possible. Unless you are running NoA with no confirmation it should NOT change or cross lanes on it's own at all.
 
Set the Speed Limit OFFSET to -20 and when you engage TACC it will use your CURRENT speed as your initial speed. This will also drastically reduce Phantom Braking.

AutoPilot will immediately seek out centering on the lane. Be sure you have good lane markings and you are in the center when engaging to avoid surprises. I've never had what you describe happen. But I can see how it can. I highly doubt your AutoPilot is broken, but it's possible. Unless you are running NoA with no confirmation it should NOT change or cross lanes on it's own at all.


How does the offset of -20 help with phantom braking?
 

ngogas

Active Member
Sep 19, 2018
1,725
1,195
Utah
Sounds like it’s just your car that is trying to kill you and failed. All kidding aside mine works like a charm. Take it to SC and have one of the technician try it out with you sitting next to them. Perhaps it will be clear to both if it's user error or malfunction in the car.
 
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mswlogo

Well-Known Member
Aug 27, 2018
8,362
7,883
MA, NH
How does the offset of -20 help with phantom braking?

It essentially disables the Auto Speed Limit Adjustment. It is believed (hard to prove) that occasionally the car picks up speeds of cross roads and suddenly the car momentarily thinks it's on a 35 mph road while traveling 70 mph on the highway. That's why it happens at bridges and overpasses (not because of shadows). So it slams on the brakes with no warning and then resumes. It happens so quickly that the display might not show a thing. When you set this magic -20 offset number it appears to disable that "feature".

I find TACC works an order of magnitude better (safer) with the -20 offset. I've tried with 0 (default) and -20 numerous times and I'm convinced it gets rid of one portion of phantom braking. It was not my idea. Someone else came up with it on one of the other forums. I didn't believe it first. I probably would not run TACC at all without this work around.

I have not tested V10 without it. Others have reported it still "Phantom Brakes" but there are several forms of "Phantom Braking". This work around addresses the worst form of it.
 
It essentially disables the Auto Speed Limit Adjustment. It is believed (hard to prove) that occasionally the car picks up speeds of cross roads and suddenly the car momentarily thinks it's on a 35 mph road while traveling 70 mph on the highway. That's why it happens at bridges and overpasses (not because of shadows). So it slams on the brakes with no warning and then resumes. It happens so quickly that the display might not show a thing. When you set this magic -20 offset number it appears to disable that "feature".

I find TACC works an order of magnitude better (safer) with the -20 offset. I've tried with 0 (default) and -20 numerous times and I'm convinced it gets rid of one portion of phantom braking. It was not my idea. Someone else came up with it on one of the other forums. I didn't believe it first. I probably would not run TACC at all without this work around.

I have not tested V10 without it. Others have reported it still "Phantom Brakes" but there are several forms of "Phantom Braking". This work around addresses the worst form of it.

VERY interesting. I would think Tesla could look at the previous 15 seconds or 500 feet or something, create a trajectory out and compare the upcoming 15 seconds or 500 feet or something and then if there is a "blip" of speed change either flag that for manual review or ignore that.
 

mswlogo

Well-Known Member
Aug 27, 2018
8,362
7,883
MA, NH
VERY interesting. I would think Tesla could look at the previous 15 seconds or 500 feet or something, create a trajectory out and compare the upcoming 15 seconds or 500 feet or something and then if there is a "blip" of speed change either flag that for manual review or ignore that.

Yes, you would think. Since it would be impossible to switch roads in a fraction of second.

It appears to be missing some sort of data filtering.

This work around seems to work. I could go a week with no phantom braking even without this work around, it's very random.
But since I put it in, it's never done it with out clear visual reasons (Albeit overly conservative). Like cars up ahead jockeying around, or a car pulled over in break down lane but not pulled over quite enough. Or a car ahead that is exiting that is clear you will clear but it panics that you might not. Those still happen. But the mystery ones on "Overpasses" seem to be alleviated, and those seemed be the most common and most abrupt. Because you could pass 10 bridges and then wham it screws up.

It's trivial to try it.
 
I agree that you definitely need to get your AP autosteer behavior looked at. Autosteer on my 3 tracks reliably in the middle of the lane. In my opinion, autosteer does better than the average person at staying centered in the lane.

I also hate to bring up this silly possibility, but are you certain that you activated autosteer in addition to TACC? Autosteer requires two quick pulls on the right stalk (whereas TACC requires only one pull) and can be confirmed as enabled by checking for the blue steering wheel on the screen. I only ask because the behavior you described sounds suspiciously like only TACC is active.
 
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jboy210

Well-Known Member
Supporting Member
Dec 2, 2016
7,290
4,958
Northern California
This sounds like the car was in Traffic Aware Cruise Control (TACC) and not Autopilot on the second occurrence. TACC does speed control and distance spacing, but does not include autosteer. When Autosteer is enabled the steering icon will turn from black/gray to blue and the warning message about keeping your hands on the wheel will appear. If you turn the wheel hard enough you can kill autosteer and TACC will still be engaged. You have to get use to checking that the steering wheel icon is blue.
 

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