JRoque
Posts: 37
Joined: Sat Jul 11, 2015 4:44 pm
Delivery Date: 29 Jun 2015
Leaf Number: 406755
Location: Miami, FL

[ANSWERED] Brakes locking

Sat Jun 10, 2017 4:16 pm

Hi all,

I have noticed this issue a few times before but last night was the clearest instance yet. You drive at ~50 MPH and firmly but briefly (~0.5 seconds) fully apply the brakes. Immediately let off the brakes and you'll notice the car will hold the brakes for you for another 1 or 2 seconds. ABS will be activated during this period.

While driving down a back road, I had some wildlife cross right in front of my car. I hit the brakes enough to not hit the animal but let go of them so the animal following me too close behind wouldn't hit me. The other driver nearly plowed into me as a result and swore me out for "brake checking" him (don't worry, he was properly responded to).

This 2013 Nissan Leaf of mine is my first ever Nissan/Japanese car and I don't know if they all do this or if there's an issue I need to report to Nissan. I can do this brake tapping at any speed all day long on any of my VW, Ford, Chevy cars.

Anyone else has experienced this issue?

JR
Last edited by JRoque on Sat Jun 10, 2017 7:53 pm, edited 1 time in total.

gshepherd
Forum Supporter
Posts: 174
Joined: Wed Apr 27, 2016 12:01 am
Delivery Date: 03 Jun 2016
Location: Seattle / Phoenix

Re: Brakes locking

Sat Jun 10, 2017 4:31 pm

That sounds like the full brake application safety feature that has made its way into modern cars. A study found drivers were afraid of literally breaking the brake pedal and often didn't depress it enough in an emergency maneuver. The computer detects a rapid foot movement from the accelerator pedal to the brake pedal. Do it assertively enough and the system will apply full braking for you. It has happened to me, and it's a bit startling, to say the least. I believe I first read about this system in Mercedes-Benz cars. The LEAF has a sensitive brake pedal response as it is, so that may make it easier to trigger the system than in other cars.

That said, if in doubt, have your dealer check the brake system... it's kind of important.
2016 LEAF SV

GerryAZ
Gold Member
Posts: 1495
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Brakes locking

Sat Jun 10, 2017 6:21 pm

Yes, I experienced it with my 2011 when someone started to move into my lane on the freeway and my only chance to avoid an accident was to hit the brakes hard because there was a sound wall next to me with only a narrow shoulder. I avoided an accident, but was very surprised that the car continued full on ABS-engaged braking with my foot completely off of the brake pedal. In desperation I hit the accelerator to avoid being rear ended and that caused the brakes to release. During testing in a safe area, I found that the brakes will release after some time delay if the car is traveling at moderate speed (perhaps 40 mi/hr or less), but the brakes will remain applied to a full stop if the car is moving at highway speed (say 55 mi/hr or higher). I was not able to conclusively determine the exact threshold speed. I complained to my dealer because the car was only a few months old at the time. Their technician was able to experience it in my car, but not in their demo so they were prepared to replace parts until Nissan told them it was normal. After they reluctantly returned the car to me without repair, I did some additional testing and confirmed that touching the accelerator will always cause the brakes to disengage immediately (regardless of speed). The 2015 is somewhat less sensitive than the 2011, but it still has the ridiculous, unsafe "safety" feature. Note: Nissan calls this "Brake Assist" and I really wish there was a way to permanently disable it.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

JRoque
Posts: 37
Joined: Sat Jul 11, 2015 4:44 pm
Delivery Date: 29 Jun 2015
Leaf Number: 406755
Location: Miami, FL

Re: Brakes locking

Sat Jun 10, 2017 7:53 pm

Hi all and thanks for the quick comments.

Oh brother, more nanny stuff. What's strange - and good - is that this is not how our 2016 Chevy Equinox behaves:
This vehicle has a brake assist feature designed to assist the driver in stopping or decreasing vehicle speed in emergency driving conditions. This feature uses the stability system hydraulic brake control module to supplement the power brake system under conditions where the driver has quickly and forcefully applied the brake pedal in an attempt to quickly stop or slow down the vehicle. The stability system hydraulic brake control module increases brake pressure at each corner of the vehicle until the ABS activates.

Minor brake pedal pulsation or pedal movement during this time is normal and the driver should continue to apply the brake pedal as the driving situation dictates. The brake assist feature will automatically disengage when the brake pedal is released or brake pedal pressure is quickly decreased.

I don't have high hopes that this "feature" can be defeated but I'd love to disable that for sure. The same people that don't allow me or my passenger to fully use my navigation above the dangerous speed of 5 MPH, won't likely let me let me apply my own brakes.

JR

LeftieBiker
Posts: 7403
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: [ANSWERED] Brakes locking

Sat Jun 10, 2017 8:43 pm

I have two thoughts on this: yes, it is better to have the auto braking disengage when the brake pedal is released - in most cases, anyway, unless the driver has lost consciousness. But it's also kind of indicative of a reckless mindset to call things like this "nanny state" tactics. The reason for the "nanny state" appears to be that we have become careless children, talking on phones, sending texts, watching videos, eating meals - all while driving. As a bicyclist as well as a driver, I much prefer "nanny states" to "baby drivers."


(With no apologies to Simon & Garfunkel.) ;-)
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

JRoque
Posts: 37
Joined: Sat Jul 11, 2015 4:44 pm
Delivery Date: 29 Jun 2015
Leaf Number: 406755
Location: Miami, FL

Re: [ANSWERED] Brakes locking

Sun Jun 11, 2017 5:39 pm

Hello LeftieBiker.

I did not say "nanny state tactics". That implies government/political mandates. I said that applying the brakes for me is "more nanny stuff". The "other" in the "other nanny stuff" also include not letting me use the navigation screens while the vehicle is moving. There are a number of options blocked when moving that defy logic. A "I'm an adult and I accept responsibility for my actions" option should be available so I can fully use the screen.

Back on point, I don't want the car to continue to press the brakes after I've commanded it to release. There's a big difference between that and crash-avoidance, for example. This is an entirely blind assumption by the car that uses little outside input other than my action to push the brake. That can make matters worse, in my view, like it just did for me a couple of days ago. At the very least, I should be able to turn off the brake assist much like I can with traction control.

JR

LeftieBiker
Posts: 7403
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: [ANSWERED] Brakes locking

Sun Jun 11, 2017 6:30 pm

It may be possible for a dealer to do it now, with their diagnostic station, but it also may not. It isn't a really common problem, though, so the easiest solution is to learn to brake a bit more gently. It's the quick transition between throttle and brake, plus hard braking that activates it, apparently, and EV drivers have found that coasting more improves efficiency, so that's a win-win.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

JRoque
Posts: 37
Joined: Sat Jul 11, 2015 4:44 pm
Delivery Date: 29 Jun 2015
Leaf Number: 406755
Location: Miami, FL

Re: [ANSWERED] Brakes locking

Mon Jun 12, 2017 4:22 am

Hello.

I feather both the accelerator and brake pedals with OCD-like presence of mind. I do that to the angst of some ICE behind me that start peaking acceleration after 30 MPH or so while I'm still accelerating evenly. It isn't a good day unless I'm >6 miles/kWh. But this is not about that. This is about emergency braking to avoid something in your path while not having it lead to an accident with the vehicle behind or unsettling your car by over-braking and ending up in a ditch.

JR

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