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Braking problem or Automatic Emergency Braking?

Discussion in 'Model 3: Driving Dynamics' started by BTinNC, Jan 8, 2020.

  1. BTinNC

    BTinNC Member

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    I have had this happen two times now in the past month, and have a service visit set for 20-Jan. I don't know if it is a braking failure, or AEB kicking in.

    In both instances, Autopilot is not engaged, I have been coming up to a redlight where the car in front of me is slowing. I let off the accelerator pedal to start slowing normally (one-pedal driving). I notice the car in front starts braking harder, the red-alert bell sounds letting me know of the upcoming collection. So I move my foot to the brake, press it normally to slow down faster (I am in complete control of the car). My car starts slowing and suddenly the brake pedal goes to the floor, the car makes a lot of noise (I think from sliding tires or ABS) and it comes to a sudden and very abrupt halt, completely scaring the sh*t out of me and disorienting me in the process. After it stops and the car in front of me moves, I can drive normally.

    The first time it happened I thought it was a fluke or maybe I hit some sand in the road or something. Then it happened again yesterday and I thought there must be something broken. So I opened a service request and am set to go to the service center on the 20th. I did some reading on this forum and see people talking about the Auto Emergency Braking system, and wonder if that is what is happening. I don't get any type of alert stating that AEB was initiated or anything like that, but the car is definitely taking over and slamming itself to a sudden halt.

    Thanks...
     
  2. ewoodrick

    ewoodrick Well-Known Member

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    How close are you when it engages?
     
  3. Needsdecaf

    Needsdecaf Member

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    Sounds like AEB is kicking in. Should probably have that checked out.
     
  4. BTinNC

    BTinNC Member

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    I believe I was within 1 car length. I was stopping on my own and would have came to a complete stop within maybe 1/2 car length. It was close, but not what I would consider 'danger close'.
    I just got a text from Tesla service asking me details. They said a virtual tech was going to review it and let me know if I need to come in. Since this happened less than 24 hours ago, hopefully it will be stored in a log and they can see if it was the AEB engaging or something else.
     
  5. jdcollins5

    jdcollins5 Member

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    The red alert was Collision Warning. Evidently you did slow down fast enough so AEB activated. I have had this happen when the car in front of me braked suddenly.

    Let us know what the virtual tech has to say.
     
  6. BTinNC

    BTinNC Member

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    Do you get any type of info alert letting you know that AEB activated? I get alerts when I get out of my lane and it has to correct the steering, so I assumed it would.
     
  7. jdcollins5

    jdcollins5 Member

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    I do not get any message for AEB, just the car braking before I have foot on brake. I do get red alert for Collision Warning.
     
  8. bedoig

    bedoig Member

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    I had this happen once. I was going maybe 5-10 mph in traffic coming off an offramp, the car in front is 10-15 feet away and then abruptly stops. I didn't want to slam on the brakes because there was an offramp full of cars behind me so I intend to slow gradually where there would probably only be a foot or two between me and the car in front. I was in full, intentional control of the situation. My car suddenly slammed on the brakes and I could feel ABS shudder through the brake pedal (my foot was already riding the brake). Glad the person behind me was paying attention. It wasn't very dramatic given the low speeds but was still jarring. Nice to have a second set of eyes watching, but not necessarily always making the same decision a competent driver would.
     
  9. BTinNC

    BTinNC Member

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    #9 BTinNC, Jan 12, 2020
    Last edited: Jan 12, 2020
    The Tesla service center just sent me a text. They said their tech reviewed the logs from my car. What I experienced was automatic emergency braking. They said the car is operating as intended.

    So, now I know.
     
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