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Steering locked up while driving a loaner

Discussion in 'Model S' started by twofieros, Mar 5, 2017.

  1. twofieros

    twofieros Member

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    Our Tesla is being serviced so I'm in a loaner. Today when pulling into traffic the steering locked up for 5-10 seconds. It would not turn at all until the service warning came up. I was then able to turn the wheel with no power assist. I nursed the car into a parking lot and did a two thumb wheel reset and recorded on my phone the same thing.

    Basically, there was a loud buzzing sound coming from the frunk near the brake pedal. When you try to turn the wheel the power assist literally would buzz and prevent any movement. This continues until the buzzing stops while at the same time the dash service warning pops up.

    We have this same model S. P85 2014 no AP. I can't help but feel concerned about this method of failure. The steering should never lock up. I should always be able to increase effort and turn the wheel. The only warning I had was the start of this buzzing sound near my feet but I think when I first heard this sound the wheel was already locked. I was stopped at a stop sign waiting to shoot across a busy divided street to go left. When I saw a gap I gunned it and found the wheel frozen. All I could do was go straight across to the curb and try to stop while leaving the most amount of road behind me while I waited for the car to release the wheel.

    Do these preAP cars have hydraulic power steering or is it simply an electric motor assist? Has anyone else had this issue? I didn't see anything similar after a search. Tesla had me do a full shut down and restart which cleared the issue and all seems fine now but I had no warning before so I'm left worrying it could happen again. Then I go on thinking it could happen to mine? I love my Tesla. I've had no major issues with it. I'm curious to hear what everyone else thinks about this.

     
    • Informative x 5
  2. MS16

    MS16 Member

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    Did Tesla ask you to immediately return the loaner?
     
  3. Drewflux

    Drewflux Member

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    Its my understanding all MS have electric assist racks.
     
  4. Petra

    Petra Member

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    Your understanding is correct--they're all electric power assist (basically an electric motor and gearset attached to the steering rack).
     
  5. Sir Guacamolaf

    Sir Guacamolaf The good kind of fat

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    Am I misunderstanding things, or this is just downright really really dangerous? Imagine your steering wheel locking up at 65mph, and then Tesla claiming "logs say the driver was snoozing" or something like that (meanwhile you are dead).
     
    • Helpful x 1
  6. AMPd

    AMPd Active Member

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    That's the first time I'm hearing something like this happening.
    Scary! Let us know what tesla says caused it.
     
  7. Drewflux

    Drewflux Member

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    Whilst I'm not suggesting having this happen to you isnt unsafe or not a pants changing event.

    Even with no assistance, the mechanical connection is still there. the vehicle should steerable @ speed. At low/ parking speeds the 19" wheels would be a wrestle to turn. Think '70s muscle car heavy.

    Having the assistance lock or fight against you is very strange, considering the double redundancy thats buit into these systems.
     
  8. K-MTG

    K-MTG Sunshade Captain of TMC

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    MKBHD had the same issue on his P100D
     
    • Informative x 1
  9. AMPd

    AMPd Active Member

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    But op is saying his steering wheel locked up and wouldn't turn at all.
     
  10. twofieros

    twofieros Member

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    The steering LOCKED up solid. All I could do was drive straight across traffic and stop perpendicular to the curb, blocking the slow lane and shoulder. You can see in the video that when I try to turn the wheel the buzzing starts which is the assist preventing me from turning the wheel. Only when the message pops up does it allow manual steering.

    Tesla had me to a power down and restart and so far everything seems fine. They should finish my car's regular service soon and now will tow my car down to swap out this loaner. Service is 3 hour drive away for me.
     
  11. ⚡️ELECTROMAN⚡️

    ⚡️ELECTROMAN⚡️ Fritterer and waster of hours in an off hand wayer

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    That's pretty scary. If true this needs to be addressed asap. I wouldn't be driving that loaner anymore.
     
    • Like x 1
  12. twofieros

    twofieros Member

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    I have a feeling since this is a loaner we will never know what the issue was/is.
     
  13. Lloyd

    Lloyd Well-Known Member

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    Probably the reason that when a suspension item is damaged that the steering box be replaced also!!
     
  14. MS16

    MS16 Member

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    One thing you can do to help the Tesla community is to get the VIN number and report the issue to the NHTSA web site. From the sounds of it, Tesla Tech Support didn't have much interest in anything other than the reboot. Critical safety items like steering or steering assist failure should be taken tacked to see if this is a one-off case, or possibly a trend.
     
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  15. ggr

    ggr Roadster R80 537, SigS P85 29

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    Most power assisted steering is done with vacuum, which you get for free with an ICE engine. The early Model S used a vacuum pump to maintain a reservoir, and pretty much off-the-shelf assist hardware for brakes and steering. When a vacuum assist system fails it FEELS like the wheel won't turn; in reality it just takes much more force than you're used to, so your brain concludes it's locked up. I've had it happen to me, and my brother lost an historic supercar when it happened to him once.

    Anyway, I don't know whether that's what happened in this case or not.
     
    • Informative x 1
  16. zwede

    zwede 2013 P85+

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    No cars used vacuum for steering assist. Traditionally on ICEs it was a hydraulic pump powered by the engine. Newer ICEs use electric assist just like Tesla.

    Power brakes used to be powered by engine vacuum and early Teslas used the same vacuum power brake booster principle with an electric pump supplying the vacuum.

    In this case it doesn't sound like the actual assist failed but rather a sensor fed bad data to the computer making it fight the driver's input.
     
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  17. SMAlset

    SMAlset Member

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    #17 SMAlset, Apr 16, 2017
    Last edited: Apr 16, 2017
    So while over on Tesla .com's forum I read a post from someone who experienced loss of steering and braking while making a turn and it reminded me of this thread. SvC said his was caused by a rotted ground stud that had to be re-welded. Not sure if this is the same type of thing that the OP had happen to him (no buzzing reported though) but does kind of sound like what MKBDH experienced. I also recall reading (maybe on this forum) about a driver who also experienced loss of steering as he was making a left across traffic on a mountain road. Thinking maybe it was on Hwy 17 in the Santa Cruz mountains. Haven't found that thread yet but in the meantime here's the link to the other forum's post:

    Alert** loss of steering and braking while driving | Tesla

    Something to keep in the back of your mind.
     
  18. Saghost

    Saghost Active Member

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    That's new, and scary. A loss of assist would be unfortunate, but understandable from any number of things and not an immediate safety issue. Locking the rack is different.

    I believe all generations of S and X use a dual pinion electric assist rack and pinion system - the steering wheel is hooked to a gear that turns a rack, and a similar rack on the passenger side is turned by an electric motor for power assist and AP when equipped.

    Since you're getting that buzzing sound and locked steering, my theory is that the rack has broken teeth near the straight ahead position on the motor side. The motor is spinning, but the teeth aren't engaged, and as a result it's grinding the gears when you try to spin the wheel, preventing it from turning. This seems like a rather extreme theory (and it is), but I'm having trouble coming up with any other reason for the steering to be locked up solid, unless the motor was directly resisting your efforts which seems unlikely.

    Of course, this theory isn't entirely compatible with a reset fixing the problem except very temporarily until the motor gets to the broken teeth.
     
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  19. sorka

    sorka Active Member

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    You're confusing power steering with brakes.
     
  20. MS16

    MS16 Member

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    This is the reason owners should report failures like this to NHTSA. NHTSA is supposed to be tracking these type of events to look for trends.
     

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