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Autosteer vs TACC?

Discussion in 'Model S' started by mbhforum, Jan 15, 2017.

  1. mbhforum

    mbhforum Member

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    Hi,

    I am picking up my 2015 85D in a week with AP 1.0. I am reading the operating manual and am a little confused by the differences between Autosteer and TACC. I understand these are the two key features that are part of the entire AutoPilot 1.0 package, but am not sure what are the differences. Can you change lanes automatically with TACC? When do you use one vs the other? Any real world feedback is helpful. I am trying to educate myself as much as possible before delivery day. I am sure the operating manual is a little outdated too since it says Autosteer is still in Beta.
     
  2. jelloslug

    jelloslug Active Member

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    TACC is speed control and AP is speed control and auto steering. One pull of the stalk enables TACC and two pulls enables TACC and auto steer.
     
  3. BerTX

    BerTX Active Member

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    Autopilot is still officially in Beta. It may always be, who knows.

    TACC is Traffic Aware Cruise Control, which is elsewhere in other cars referred to as ACC, or Adaptive Cruise Control. It is normal cruise control, except uses sensors to "see" cars in front of you and change the speed according to the traffic. If the car in front of you is going slower than your speed setting, it will slow down and keep a driver-set following cushion between you an the car ahead. This does no steering, the driver is in control of that. Putting on the turn signal to pass the slower vehicle in the same lane will cause the TACC to resume your speed setting, unless there is also a car ahead of you in that lane, in which case it will slow to give your cushion behind that car.

    Autosteer takes control of the steering of the car to keep it in the current lane AND sets the TACC to control the speed. You will need to keep your hand(s) on the wheel, or you will be reprimanded by the car. Putting on your turn signal in this case causes the car to change lanes. Not fully "automatic", as the car won't change lanes of its own volition.
     
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  4. mbhforum

    mbhforum Member

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    Thanks! So with TACC, hand on the wheel and your steering but no foot on the pedal. Got it!
     
  5. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    Correct, you will see this indicated on the instrument cluster by the blue icons.

    Top left icon is the speed control setpoint. Top right icon is the autosteer icon.

    If you are manually driving, both are gray.

    One pull on stalk engages TACC. When TACC is engaged (speed control only), the top left icon will be blue, with the set speed shown. Top right autosteer icon will still be gray.

    Two pulls on stalk engages autosteer. When autosteer is engaged, BOTH top left icon (speed control) and top right icon (autosteer) will be blue. You will also get an engagement audio feedback tone. Additionally, the object that autosteer is using to control the car's steering will be shown in blue in the display's center (usually lane lines, but sometimes the car you are following).

    There is no such mode where autosteer is engaged but TACC is not.

    Push forward on the stalk or tap the brake to disengage all automatic control (turns off BOTH autosteer and TACC). You can disengage autosteer only and leave TACC engaged by turning the steering wheel strong enough, but I don't recommend this. The safe course of action If the driving situation has gotten to where autosteer is not appropriate is to disengage both, and then reengage at a later time when the driving situation has improved.

    I recommend a good read of the owner's manual and careful practice -- driving with TACC and autosteer requires a bit of a learning curve to get used to it and do it safely.
     
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  6. mbhforum

    mbhforum Member

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    Thank you. I certainly understand the differences a lot better. I read these sections over and over in the manual and I was still a little unclear.
     

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