TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Brake failure warning down steep grade

Discussion in 'Model S: Driving Dynamics' started by Gtrain, Oct 11, 2015.

  1. Gtrain

    Gtrain Member

    Joined:
    Sep 11, 2015
    Messages:
    7
    Location:
    newport beach, CA
    Wondering if anyone else has experienced something similar. I have now owned my 85D for nearly 3 weeks and we decided to take the car for a long trip from SoCal to the Monterey area. Towards the end of the trip, we were driving down a steep grade when the low brake fluid alert came on, along with the red brake failure light. The brake pedal feel did not change at the time. The light stayed on until we returned to flat ground. I brought the car into Tesla service the next day (they were very accommodating and responsive) and I was told that their logs confirmed the warning but that the fluid was only 4 "tablespoons" down from the max level and well within recommended operating levels. They suspected that the level was just low enough to trip the sensor on a steep grade as the fluid shifted below the sensor level. Although this was a steep grade (about 10%), it's not like these types of grades are all that uncommon. I would have to assume that other people are experiencing the same issue if my fluid was just slightly lower than the max level. They also suspected that the car was never topped off at delivery but I find that hard to believe given the car has already been fully "inspected" and topped off on at least one other occasion recently when I had to bring the car in for a windshield washer reservoir that leaked all my fluid on my garage floor. Love the car and the service from Tesla but have not had good luck so far in these first 3 weeks of ownership.
     
  2. AmpedRealtor

    AmpedRealtor Active Member

    Joined:
    Jun 30, 2013
    Messages:
    4,701
    Location:
    Buckeye, AZ
    How is the brake light coming on, and Tesla subsequently diagnosing as a non-issue constitute "not had good luck so far in these first 3 weeks of ownership"? You also said you loved the service. Sorry, I don't mean to pick on you, but it doesn't sound to me like there's anything to complain about in this situation. Your brakes didn't fail, Tesla answered the question, and you haven't had any issues since, correct?
     
  3. CatB

    CatB Member

    Joined:
    Mar 2, 2013
    Messages:
    661
    @AmpedRealtor - OP also mentioned a leaky windshield washer reservoir, which I'd consider bad luck. And I agree car shouldn't have been low on brake fluid only 3 weeks after delivery.

    @Gtrain - thx for posting, good to know brakes were fine and how this happened. I am actually a bit spoiled by Tesla service because when something like this happens, I just call them right then. I don't know if they could have saved you a visit by checking the logs remotely, but they've been able to reassure me when something is inconvenient vs dangerous.
     
  4. Gtrain

    Gtrain Member

    Joined:
    Sep 11, 2015
    Messages:
    7
    Location:
    newport beach, CA
    @AmpedRealtor: I'm not sure what about my post prompted you to write such a defensive reply. I think most would agree that having a cracked windshield washer reservoir 3 days after receiving the car and then needing to schedule an emergency visit with the service center for a potential brake failure the following week, would qualify as an unlucky series of events. I agree that I should consider myself "lucky" that I am still alive and the service center confirmed that the brake warning light was a false alarm. For the record, I am a staunch advocate for Tesla. I am also ani investor and would like nothing more than for the company and EV cars to succeed. In my mind, this forum is a place whereby people can exchange ideas and help each other out. In my opinion, your reply was not constructive in any way and unfairly critical for no apparent gain.

    @CatB: Thank you for your reply and support.
     
  5. rpo

    rpo Member

    Joined:
    Jun 12, 2014
    Messages:
    200
    Location:
    Washington
    I drive down a 26% grade frequently in Seattle. No warnings have ever come on.
     
  6. swaltner

    swaltner Member

    Joined:
    Oct 13, 2012
    Messages:
    495
    Location:
    Kansas, USA
    @Gtrain, is there any chance you were holding on the brake pedal for a long period of time, and overheating the physical brakes, leading to this alarm? You say the brake pedal feel didn't change during this time, so that doesn't really jive with this potential source of the error. Just curious if there's another reason for the alarm other than the brake fluid reservoir not being totally full. *If* you had the regen mode set to low and were using the brake pedal, I'd think you'd have better results with the regen set to Normal and not using the brakes except in short bursts.

    edit: you did say the alarm was for low brake fluid, so this is probably totally off base. It's just the first thing I think of when someone mentions coming down a steep descent...
     
  7. Gtrain

    Gtrain Member

    Joined:
    Sep 11, 2015
    Messages:
    7
    Location:
    newport beach, CA

    One of the nicest things above the regenerative braking system is that you don't end up using the brakes much at all. That said, on a steep grade, a couple taps on the brakes every so often is sometimes necessary to control the speed. My point in stating that the brakes did not get spongy is to simply point out that, indeed it was obvious that there was enough pressure in the lines to maintain pedal feel. So, while the warning may have stated that the "fluid is low", it clearly was not low enough to effect the subjective feel of the pedal in depressing it. Without an objective measure of the actual fluid level, however, it is impossible to say how long that would remain true before the fluid would be low enough to produce a soft or unresponsive pedal. At the time of the descent, I had no way of knowing how or why the light was on. Nor, could I assume that it would simply "resolve itself" once I got to the bottom of the hill.

    I have had nothing but fantastic experiences with Tesla service thus far. I think we all can say that their willingness to go above and beyond is unprecedented within the auto industry. My original post was not meant as a knock against Tesla in any way, shape or form. Nor was I trying to elicit sympathy for what I would still consider to be an "unlucky start to my ownership experience". I still love Tesla, the car, and their mission. I continue to be an investor and a staunch advocate on their behalf. My only reason for posting my experience was to inform others and to gather thoughts and ideas about something that still in my mind does not entirely add up. Although the brakes checked out OK, I would still submit to anyone (as has been suggested by those who say they have not experienced a similar thing), that it is abnormal for the light to come on simply due to the level being "4 tablespoons down from max" while coming down a 10% grade. Furthermore, the fact that it was low by even 4 tablespoons less than 3 weeks from taking delivery on a brand new car begs the question of why or what caused that to be the case. The warning light was indeed confirmed by the car logs when pulled by Tesla so I know that it was not merely a hallucination on my part.

    Thank you to those who have offered helpful suggestions and posts.
     
  8. Soolim

    Soolim Member

    Joined:
    Jun 11, 2015
    Messages:
    849
    Location:
    Vancouver, BC, Canada
    I am guessing that the prolonged steep grade prompted the alarm due to the brake fluid level being below sensor detection level for a long period of time. I imagine that the brake level sensor would have a time delay built in to account for short period of driving with steep grade (normal occurrence) without nuisance alarm. I would suggest checking the brake fluid level more frequently to see if the level continues to fall.
     
  9. muleferg

    muleferg Member

    Joined:
    Dec 15, 2013
    Messages:
    742
    Location:
    North Wilkesboro, NC
    I drive in the mountains of NC. Never had that happen.
     
  10. California85D

    California85D Member

    Joined:
    Sep 15, 2015
    Messages:
    9
    Location:
    California
    Today on the way to work I got the low brake fluid warning. My car is less than a month old. I guess I'll call Tesla. Was just googling to see if anyone had a similar problem and found this thread.
     
  11. Khatsalano

    Khatsalano Member

    Joined:
    Mar 21, 2015
    Messages:
    648
    Location:
    San Mateo, CA
    Drove lots of mountains to Tahoe and to Canada and back to California. Never seen this before.

    - K
     
  12. Cyclone

    Cyclone Active Member

    Joined:
    Jan 12, 2015
    Messages:
    4,394
    Location:
    Charlotte, NC
    Once of these days I want to take the S through Fancy Gap at the NC/VA border and check out how horrible my numbers are NC -> VA and how amazing my numbers are VA -> NC! :)
     
  13. Mille Pun

    Mille Pun Member

    Joined:
    Jun 21, 2015
    Messages:
    111
    Location:
    HK
    Just took delivery, and got this brake fluid warning on a park mode uphill. It's gone when return to flat road.....still no idea on the problem. False alarm or software issue.....?
     
  14. SR33323

    SR33323 New Member

    Joined:
    Sep 28, 2015
    Messages:
    2
    Location:
    Churchville, Pa
    I have had my 85D for two weeks and have experienced this same problem twice. Both times occurred when I was exiting my driveway on a relatively shallow decline, and both resolved after a minute or so of being on level ground. I called the service center today, and they said that I'd have to bring the car in for them to check it out. He suspected that it has something to do with placement of the sensor, or that the fluid could be "just low enough" for it to detect it on a slope. In either case, this shouldn't be happening in a new car.
     
  15. SR33323

    SR33323 New Member

    Joined:
    Sep 28, 2015
    Messages:
    2
    Location:
    Churchville, Pa
    To be clear, I love my new car. My hope is that they figure out why this is happening and fix it so that others don't experience this problem.
     
  16. Mille Pun

    Mille Pun Member

    Joined:
    Jun 21, 2015
    Messages:
    111
    Location:
    HK
    Sr33323, how is it going?
     
  17. bancroftc

    bancroftc Member

    Joined:
    Sep 21, 2015
    Messages:
    179
    Location:
    Austin, TX
    I had this occur this morning. I was on a downhill grade with hill hold engaged, and all of a sudden I got the "Brake Fluid Low" warning along with the red brake hazard indicator. The slope I was on was not that steep. In fact the grade at the entrance to my neighborhood is quite a bit steeper and I've never seen this before. Anyways, as soon as I got back on flat ground the warning went away. I've had no apparent issues with the brakes otherwise. 3 month old 85D.

    I guess I'll let it lie for now and call service if it pops up again.
     
  18. rdverb

    rdverb Member

    Joined:
    Jun 25, 2015
    Messages:
    9
    Location:
    Pebble Beach, CA
    Has anyone seen evidence of brake fluid leakage? I've had my 85D since August (5 mo), including a 4200 mile road trip over the Sierras, through NV, ID, MT, UT, and back to CA. No brake warnings in the mountains or on steep driveways locally. Maybe just a strange run in October?
     
  19. bancroftc

    bancroftc Member

    Joined:
    Sep 21, 2015
    Messages:
    179
    Location:
    Austin, TX
    I have not seen any evidence of brake fluid leakage. I'll double check though. I also have not seen the brake fluid warning return in the past 24 hours, so I'm hoping it was just a fluke.
     

Share This Page