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Autopilot issue when car in front changes lanes

Discussion in 'Model X: Driving Dynamics' started by mblanshard, Aug 26, 2016.

  1. mblanshard

    mblanshard Member

    Apr 7, 2016
    Raleigh, NC
    Hello All,

    I've had my X for about 2.5 weeks now and have put about 2.5k miles on it with about 2000 of them being with AP. I've noticed that the following happens:

    • I've got AP set to on and there's a slower car in front of me so I'm going less than the maximum set speed
    • The slower car moves over to the right lane
    • My X speeds back up to the set speed and then suddenly hits the brakes hard as I start to overtake the car that I am passing
    I've also noticed this when the car that was in front of me uses the exit ramp and I start to pass them as they slow down to exit and the X hits the brakes hard as if it isn't noticing that the car is over in the other lane properly.

    Has anyone else experienced this? I suspect that this is either a software issue or a faulty sensor. I'm going to get the SC to take a look at it in the near future since it's a safety issue.
  2. tezzla

    tezzla Member

    Jul 14, 2013
    I believe it's like that for all cars. It shouldn't happen all of the time, but mine definitely does this every once in a while.
  3. chris5639

    chris5639 Member

    Jul 8, 2016

    Yes, I've experienced this as well on my S. With or without auto-steering activated. I don't like hard braking or acceleration for cruise control so I tend to just go manual for now. I wish there was a feature to set a range for car distance than an absolute number.
  4. beeeerock

    beeeerock Active Member

    Mar 12, 2015
    Kamloops BC Canada
    Not sure if what I've seen is the same thing, but there have been a few instances where the car in the right lane started wandering back toward my lane as I started to overtake and AP hit the binders. I assume AP was anticipating the other car to return to the lane it had been in.

    I've also had the brakes go on when overtaking slower vehicles on left hand bends going over a crest curve. The other car appears to be in front of me and the lines aren't visible far enough out to be *sure* we'll pass safely on the left. I anticipate that now and counteract the slowdown with my right foot.
    • Like x 1
  5. VerityZooms

    VerityZooms Member

    Apr 19, 2016
    Chicago, IL
    Same issue, but it's pretty easy to mitigate:

    I tend to avoid the TACC except on suuuuuper-empty roads. In mild traffic, I set it to a low speed (i.e. the speed-limit — here in Chicago, that's 20% slower than anybody else is going :p), and then modulate my *acceleration* with the pedal, as normal. I just use Autosteer for lane-keeping and lane-changing.

    I basically only use TACC speed-management when there's 0-10% traffic, or 90-100% traffic, honestly.
  6. davidc18

    davidc18 Member

    Apr 25, 2015
    So. FL
    Try using a follow setting of 7 - has been working well me.

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