Grabby Brakes?

[TimLee]

Hello,
I'm sorry but "dangerous" and "unintended movement" just don't apply.Don

I disagree completely with you Don.
The degree of significant torque forward movement that the LEAF does is way more than any properly designed automatic transmission ICE with appropriate engine RPM control.
I have experienced the same unintended acceleration that Audi had in 1986 on a Ford product that was built in Germany in 1988.
It was caused by defective throttle position sensors / RPM control that caused the engine to go to high RPM rapidly while initially at a stable throttle.
Now admittedly the Audi deaths caused by that were due to driver error, inattention and failing to respond to the sudden movement forward, or in the worst cases on the Audi hitting the accelerator instead of the brake. But the defective product design is what ended up with human performance error causing unnecessary deaths.
The LEAF creep is no where near that bad, or as dangerous.
But it is stupidly unnecessary and creates a similar unnecessary risk of human performance error resulting in a serious unnecessary accident.
On an automatic transmission ICE it would be expensive to make it have completely zero forward movement.
But to add unnecessary and unintended forward movement to an electric vehicle is just downright stupid and creates unnecessary accident risk.

 

[kubel]

Anyone else experience pulsing brakes when using consistent brake pressure after the brake update? It's as if the brakes start to grab, then the car lets go slightly, then they grab, etc... Happens about twice per second in a rhythm (fixed just like grabby brakes, completely let off brake, then press brake and problem is gone). It's not violently pulsing, and there's no feedback in the pedal. I've added it to my list of things to fix when I go in for my battery check (aka driver check) next month, just curious if anyone else has experienced this.

 

[garsh]

I have to work at making my brakes grabby but it's usually gone after the surface rust is worn off the rotors.

I've had that happen after not driving the car for a few days. This is different.

If you take your foot off the brake on ANY car (except manual trans) it is going to move as the driver intends.

But it doesn't. It keeps braking until the car comes to a complete stop, even after taking your foot off the brake. It's quite disconcerting.

 

[planet4ever]

If you take your foot off the brake on ANY car (except manual trans) it is going to move as the driver intends.

But it doesn't. It keeps braking until the car comes to a complete stop, even after taking your foot off the brake. It's quite disconcerting.

In my case I've never had time to see what would happen if I took my foot off the brake. I'll be creeping in traffic, and press lightly on the brake. I come to a sudden, lurching, head jerking, stop as if I had just slammed on the brake. It doesn't happen all the time, but when it does there is no question that it is abnormal.

Ray

 

[DurkaDurka]

Just a data point. I had the issue, did the TSB...basically went away for a number of months, now it's back.

 

[Petecomp1]

Mine does this also (intermittent grabbing at very low speed). 2013 SV delivered March 12 2013, currently 1418 miles. In this rural setting I can usually get away with only "B" braking (no one fully stops at a stop sign with no cars in sight for miles, unless the sherrif's watching . It's not dangerous but certainly a bit annoying when driving in town and/or trying to impress my spouse on how smooth this car is. Please post any Nissan TSB's or firmware updates relating to this, thanks.
-Bill P.

 

[69800]

I have a 2012 with 12000 miles and just the last 1000 miles or so I am noticing this problem showing up. My car has never been to the dealer so no updates. I will say though that I drove around the other day putting it in Neutral at every stop and could no get it to reproduce once. I think it may be connected to regen transition to brakes. I will probably get the TSB NTB12-086a

 

[FremontRider]

I experienced the grabby brakes and had the dealer update the software two days ago. The grabby brakes are gone at low speed and brakes feel firm. However, in eco mode, the regen seems more pronounced. My usual commute use of 4 and sometime 5 bar is now using 6 after the update. I think I like it better before the update.

Anybody has the same experience of using more energy after the update?

 

[ksnogas2112]

I experienced the grabby brakes and had the dealer update the software two days ago. The grabby brakes are gone at low speed and brakes feel firm. However, in eco mode, the regen seems more pronounced. My usual commute use of 4 and sometime 5 bar is now using 6 after the update. I think I like it better before the update.

Anybody has the same experience of using more energy after the update?

IIRC the grabby brake fix has a tendency to also include the dash reset to make the GOM even more conservative than it already was. I can't find the thread I'm think of.

 

[DaveEV]

I had NTB12-086a applied to my car while it was in for it's 2nd annual battery check.

Unfortunately, they had to keep it overnight as they had issues flashing the brake module and has to escalate it with Nissan. But in the end they got it sorted and I had my LEAF back after lunch.

I haven't tried to duplicate the grabby brake scenario yet, but I have noticed that the brake pedal seems more sensitive in general. If I had to guess I'd say it also feels like more friction brakes are being used than before as well. I also had the brake fluid flushed at the same time since it's been 2 years.

I recall some others mention that more friction braking seemed to be used - how do those people feel after driving the car a while with the reflash? My commute is on surface streets so any significant reduction in regen efficiency should be noticeable over time.

 

[bowthom]

If you take your foot off the brake on ANY car (except manual trans) it is going to move as the driver intends.

But it doesn't. It keeps braking until the car comes to a complete stop, even after taking your foot off the brake. It's quite disconcerting.

Different issue, I was talking about car at rest, lift foot off brake = car rolls.

 

[bowthom]

Hello,
I'm sorry but "dangerous" and "unintended movement" just don't apply.Don

I disagree completely with you Don.

The LEAF creep is no where near that bad, or as dangerous.
But it is stupidly unnecessary and creates a similar unnecessary risk of human performance error resulting in a serious unnecessary accident.
On an automatic transmission ICE it would be expensive to make it have completely zero forward movement.
But to add unnecessary and unintended forward movement to an electric vehicle is just downright stupid and creates unnecessary accident risk.

It's neither stupid or unneccesary, there is a specific reason for the creep. It pre-loads the drive train to save those parts from the instant torque which will "shock load" the components and cause early failure. It gets rid of the annoying clunk too.

No need to use terms such as "dangerous" and "unintended movement" to sensationalize it either. If you keep your foot on the brake the car will not move. My Leaf barely moves when I release the brake.

 

[TimLee]

No need to use terms such as "dangerous" and "unintended movement" to sensationalize it either. If you keep your foot on the brake the car will not move. My Leaf barely moves when I release the brake.

I disagree.
The NHTSA review of creep that ended up making the recommendation that creep should be required on hybrid / electric vehicles in REVERSE, noted a huge variation in the amount of creep in ICE vehicles that were tested. The 2011 LEAF is definitely towards the excessive high end of the range of creep. Markedly more creep than the other two ICE vehicles I have, a 2009 Altima and a 1994 Taurus SHO.
NHTSA did not require creep in forward.
Tesla gives the driver the option to eliminate it for forward.
Nissan should do the smart intelligent thing and do the same.

 

[JeremyW]

I rented a 13 leaf up in Sac when I was up there for work, and it too had the grabby brake issue. Unacceptable.

 

[atlleaf]

i have the same felling..

does this apply on a 2011 leaf?

But i dont want it done, if it use less regen.

 

[TomT]

Yes it does and no, it has no affect on regen.

does this apply on a 2011 leaf?
But i dont want it done, if it use less regen.

 

[Stoaty]

I got the update for grabby brakes a couple of weeks ago while doing 2 year battery check and other software updates. My observations so far:

--problem is decreased at least 80% - haven't noticed significant issues since the update
--braking in general seems smoother and regen is applied more consistently when using brakes

Very happy with the improvement, no negative side effects noted.

 

[lion]

I rented a 13 leaf up in Sac when I was up there for work, and it too had the grabby brake issue. Unacceptable.

I'm having this issue with my 2013 SL as well, to the point passengers are noticing it. Very annoying, and I hope they will eventually release an update for the 2013 as well. I did not experience this issue in the 2012 I test drove.

 

[DeaneG]

While my 2011 no longer has the frighteningly grabby brake problem, after the software fix, they are still somewhat grabby at low speeds making it difficult to drive smoothly. It really makes me wish for stronger e-regeneration plus "normal" brakes a la Tesla.

 

[mbender]

I just want to chime in here (or "add a data point" as someone else put it), but I have inconsistent brake issues on my 2012, and apparently the technical bulletin did not apply to it, so they didn't do anything during my first service check. But there is no question that at low speeds, sometimes they are soft and sometimes very 'touchy' and it is unpleasant, if not unsafe, not being able to depend on a consistent pressure to apply.

I'm not sure what to do at this point, besides "squawking" here.