69800
Well-known member
low speed only... never had a problem with high speeds
Grabby Brakes?
- Thread starter rmakela
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69800
Well-known member
I am going to look into the VDC connection.....
tps
Well-known member
I've had both the low speed "grabby" brake problem, as well as the low speed problem where I have to push the brakes a lot harder than normal. Neither happen often, but they definitely get my attention. I've not had a similar problem in any other car.
While this has not yet caused a problem, the "grabby" brakes could be a contributing factor to me getting rear-ended, because it causes me to stop inappropriately quickly. And the (not total, but significant) loss of braking action could cause me to rear-end someone.
Both situations require extra attention on either my part, or the following driver's part. I would say that alone is a BIG reason that this is a completely undesirable and potentially unsafe behavior of the LEAF's braking system.
A car's response to driver input, if anything, should be totally predictable, and this is definitely not.
As a side note, the "checkout" which pilots get when they fly different airplanes alerts them to eccentricities of a particular model of aircraft so they can deal with them appropriately. If "brake assist" is trying to fix the problem that the driver inappropriately "pumps the brakes" in a car with ABS, it seems the wrong way to go about it. How about a checkout ride with a competent driver?
Back to topic, IF grabby brakes are a side effect of "brake assist", IMHO it creates a bigger problem than it solves.
For this issue alone, I would significantly reduce the LEAF's safety rating. Maybe this will get Nissan's attention!
While this has not yet caused a problem, the "grabby" brakes could be a contributing factor to me getting rear-ended, because it causes me to stop inappropriately quickly. And the (not total, but significant) loss of braking action could cause me to rear-end someone.
Both situations require extra attention on either my part, or the following driver's part. I would say that alone is a BIG reason that this is a completely undesirable and potentially unsafe behavior of the LEAF's braking system.
A car's response to driver input, if anything, should be totally predictable, and this is definitely not.
As a side note, the "checkout" which pilots get when they fly different airplanes alerts them to eccentricities of a particular model of aircraft so they can deal with them appropriately. If "brake assist" is trying to fix the problem that the driver inappropriately "pumps the brakes" in a car with ABS, it seems the wrong way to go about it. How about a checkout ride with a competent driver?
Back to topic, IF grabby brakes are a side effect of "brake assist", IMHO it creates a bigger problem than it solves.
For this issue alone, I would significantly reduce the LEAF's safety rating. Maybe this will get Nissan's attention!
GeekEV
Well-known member
That's one statement I think everyone can agree with.tps said:
planet4ever
Well-known member
I had a problem with a leaking ABS actuator, which Nissan replaced under warranty. (Thread: Brake system warning and error) That seems to have taken care of my grabby brakes.
Ray
Ray
FairwoodRed
Well-known member
My Grabby Brakes continue to rear its head. Not as bad as before the software update, but still an annoyance. And it turns out that I have pinpointed the conditions that cause it to happen on my car.
Slow gradually, like if you are trying to get mostly regen. Let up only partway on the braking force (because I realized that I will stop too far back from the car ahead). Apply more braking, because I’ve rolled far enough forward that I now need to stop. That third step is guaranteed to grab.
I also know how to prevent brake grab on my car. Simply let off the brake pedal completely between applying more force. I now view my brakes as one-time use only. If I have to ease up for any reason, then I need to fully release the brake pedal before I brake again.
Slow gradually, like if you are trying to get mostly regen. Let up only partway on the braking force (because I realized that I will stop too far back from the car ahead). Apply more braking, because I’ve rolled far enough forward that I now need to stop. That third step is guaranteed to grab.
I also know how to prevent brake grab on my car. Simply let off the brake pedal completely between applying more force. I now view my brakes as one-time use only. If I have to ease up for any reason, then I need to fully release the brake pedal before I brake again.
tps
Well-known member
Today I had the "loss of braking" problem again. It happened as I was pulling into a parking space. I was only moving maybe 5 MPH or so, but when I pressed the brake pedal to ease to a stop, I got the pedal resistance I expected, but no braking! I quickly realized this and really stepped on the pedal and the car jerked to a stop. When I got out, I found the front bumper just a couple inches from making destructive contact with a very high curb.
Here's my theory: In the LEAF the braking is normally blended between the hydraulic disc brakes and the regenerative braking system. When the speed gets rather slow, apparently the regen braking drops out and the disc brakes take on the full braking load. I'm thinking there is some "race state" which occurs in the software which causes the algorithm to get confused, and shunts most of the hydraulic pressure away from the brakes thinking that the regen system is braking. But in fact, the regen system has decided drop out, leaving me with very little braking.
Applying substantial pressure suddenly to regain braking before I hit what's in front of me caused the car to do a panic stop, which even from 5 MPH was spectacular enough that the spectators who saw it made interesting comments.
I sure hope Nissan can fix this, because one day it WILL cause a crash. They are lucky I am not generally a distracted driver, and that I am not prone to tailgating, or I would have likely crashed already.
Here's my theory: In the LEAF the braking is normally blended between the hydraulic disc brakes and the regenerative braking system. When the speed gets rather slow, apparently the regen braking drops out and the disc brakes take on the full braking load. I'm thinking there is some "race state" which occurs in the software which causes the algorithm to get confused, and shunts most of the hydraulic pressure away from the brakes thinking that the regen system is braking. But in fact, the regen system has decided drop out, leaving me with very little braking.
Applying substantial pressure suddenly to regain braking before I hit what's in front of me caused the car to do a panic stop, which even from 5 MPH was spectacular enough that the spectators who saw it made interesting comments.
I sure hope Nissan can fix this, because one day it WILL cause a crash. They are lucky I am not generally a distracted driver, and that I am not prone to tailgating, or I would have likely crashed already.
RogerMondo
New member
- Joined
- Mar 24, 2014
- Messages
- 3
I have been noticing "grabby" brakes on my 2013 LEAF and was surprised to find this discussion from 2011 with no resolution to the problem.
Last week I took my car to the local Nissan dealer for its 5k mile checkup, and mentioned the braking problem, and sent them the link to this discussion. The service rep looked into it, and said that Nissan has a fix due out today (Mon Mar 24, 2014). She did not know what it involved (software, hardware, adjustment...) but I have an appointment for it tomorrow, so should find out soon.
Check with your dealer to find out if they know of this.
Last week I took my car to the local Nissan dealer for its 5k mile checkup, and mentioned the braking problem, and sent them the link to this discussion. The service rep looked into it, and said that Nissan has a fix due out today (Mon Mar 24, 2014). She did not know what it involved (software, hardware, adjustment...) but I have an appointment for it tomorrow, so should find out soon.
Check with your dealer to find out if they know of this.
GeekEV
Well-known member
Please do follow up. If you can, find out the service bulletin number and post that along with which models it applies to (all, only 2013, etc.).
Thanks!
Thanks!
RogerMondo
New member
- Joined
- Mar 24, 2014
- Messages
- 3
Yes that would be the one. They said it was a software only update, and with just one day of driving the breaking performance is noticeably improved and not grabby at all!
GeekEV
Well-known member
Only for 2013/2014s? :-(
RogerMondo
New member
- Joined
- Mar 24, 2014
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After two days of driving with the brake update, I am curious about the change. I have observed that there seems to be much less regenerative braking - as indicated by the five spots to the left side on the dashboard's power usage indicator. Even traveling at 30 MPH and breaking to a full stop at various rates (no other cars around), no more than the first two spots light up. I recall being able to get all 5 to light before. Does this mean more use of the mechanical brakes, and less power recaptured?
I had a Prius for 6 years and never had to replace the brake pads. It would be helpful to have an indication of when the mechanical brakes are being employed on the LEAF.
I had a Prius for 6 years and never had to replace the brake pads. It would be helpful to have an indication of when the mechanical brakes are being employed on the LEAF.
DarkStar
Well-known member
That sounds about right (unfortunately).RogerMondo said:
TickTock
Well-known member
Yes - fewer regen bubbles ("spots to the left side") means less regen and the difference is friction. The four regen bubbles only represent 50% of the total regen capability so even though you see all four you may only be just over 50% of the Leafs full regen capability. Noone knows why the available regen works the way it does (maybe even NissanRogerMondo said:
) but generally it increases as you use it (brake) and decreases as you accelerate. I have a modified gid-o-meter which chirps at me proportionally to the amount of friction braking being applied so I can optimize my regen (minimize friction) without taking my eyes off the road. Also have added this feature to CANary as well along with a bar graph indicator. I think LeafSpy has added the bargraph recently but don't think the audible cue is there yet.AndrewAndDebbie
New member
Our Sunderland built Leaf Tekna has the grabby brake problem. It started around 500 miles. We have about 2000 miles on the car now and it has never gone away.
I'm going to see if Nissan GB have a patch or are even aware of the problem.
I'm going to see if Nissan GB have a patch or are even aware of the problem.
Flashman
Well-known member
For a leased vehicle... has anyone ever successfully refused an update? are they mandatory?
I have learned how to work my way around the touchy brakes and do not want to sacrifice the extra regen the car has now.
I have learned how to work my way around the touchy brakes and do not want to sacrifice the extra regen the car has now.
Flashman
Well-known member
Wow, really?
Gee... thanks, now I can go face the world without the fear of change cause everything will just be better after all!!
No thanks...
Here's a thought.. maybe research the update and learn if it will be better first.
Back to the original question... does anyone know if these updates can be optional? are all mandatory?
Has anyone ever said to a dealer... I prefer not to have that (any particular) update and the dealer said ok?
One would think they could be similar to computer Software updates having some as optional and some as mandatory.
Does anyone know if this is the case?
