Brakes problem!!

Had pretty weird situation 2 days ago when starting up Leaf...
Like usual I pushed brake pedal, pressed a button, and as it was clunking I heard and felt some click in the brake, then I put car in drive (while holding a brake) and the car started moving!! and it kept moving as I was frantically trying to brake harder, and it took considerable amount of force to stop the car...
After I released the brake and pressed again it responded normally.
While I moved probably only a foot or two during that incident, I was kind of scared... But it never happened again, so not sure if Nissan shop will be able to reproduce it...

Anyone had similar experience?

That would certainly have got MY attention. Not good at all, what if a someone was back there and you couldn't get it stopped? I'd report that one to the dealer ASAP, even if you don't think they can reproduce it. It's a safety issue.

Anyway, thanks for the heads up, if it ever happens to me, I'll know to let the brake up for a sec and/or go for the parking brake.

davewill said:

That would certainly have got MY attention. Not good at all, what if a someone was back there and you couldn't get it stopped? I'd report that one to the dealer ASAP, even if you don't think they can reproduce it. It's a safety issue.

Anyway, thanks for the heads up, if it ever happens to me, I'll know to let the brake up for a sec and/or go for the parking brake.

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I don't think parking brake would have been more effective... it take a second or so to engage, and I stopped the car probably in less then that... It all happened pretty fast...

Yup, this happened to me today. I had to really step on the brake to stop the car. I'm trying to reproduce the incident.

That sounds like a variation on this thread: http://www.mynissanleaf.com/viewtopic.php?f=4&t=3916

I really like Nissan!
On Friday I got a call from Nissan tech, apparently they are on top of this forum! (I haven't reported the problem anywhere else...)
They'll be in Seattle tomorrow and would like to take a look at the car to read logs/error codes if any.
I still can't reproduce the problem though... Let's see if they'll be able to find anything...

UkrainianKozak said:

I really like Nissan!
On Friday I got a call from Nissan tech, apparently they are on top of this forum! (I haven't reported the problem anywhere else...)

Click to expand...

Wow! Well done Nissan!

+1
They must have figured out who you are through the VIN number on your profile. If not, that's pretty scary. :lol:

After reading about the issue in the forum, yesterday I believe I noticed/heard/feel the clank in the brake pedal. I was in the garage, so there was no room for tests. I turned it off, with the foot off the pedal. Waited about 10 seconds and started again (press the pedal then the button) without any clanking and the brake worked fine when car was put in reverse. No parking brake was applied at all. I believe I had the driver door open when I started the car first time.

ABS systems make noises at times, I would caution people from believing they have a brake issue at every noise or irregular pedal feel.

EVDRIVER said:

ABS systems make noises at times, I would caution people from believing they have a brake issue at every noise or irregular pedal feel.

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Good advice. I've certainly noticed that because the LEAF is so much quieter, I'm far more aware of the myriad of noises that cars make. Most of these would have been masked by the sound of the ICE in my old cars so I'd never heard them before. :lol:

EVDRIVER said:

ABS systems make noises at times, I would caution people from believing they have a brake issue at every noise or irregular pedal feel.

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It wasn't like ABS system. It felt like I had no power brakes/brake assist or whatever it is called in leaf.
It was exactly the same feeling as if you try to brake on ICE car with engine off, except leaf was on, and I just put a shifter in drive and car started moving unexpectedly when I was applying regular moderate pressure on brakes. I was driving soo many different cars for 25 years, so believe me I know what feels right and what not...
It was not normal operation. The only good thing is that happened only once, and I already know that if I feel that knock on the pedal when I start my leaf (I'll have it in my permanent scary memory), I would pump the brake before putting it in Drive.

There is a large capacitor bank that stores energy for the power brake hydraulic booster pump when the car is off, 1540 Farads!..perhaps it got drained. See it here

http://www.mynissanleaf.com/viewtopic.php?f=8&t=3935&hilit=farad

Herm said:

There is a large capacitor bank that stores energy for the power brake hydraulic booster pump when the car is off, 1540 Farads!..perhaps it got drained. See it here

http://www.mynissanleaf.com/viewtopic.php?f=8&t=3935&hilit=farad

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It is not for "hydraulic booster" it is for electric parking/emergency break, it has nothing to do with power brakes...

UkrainianKozak said:

Herm said:

There is a large capacitor bank that stores energy for the power brake hydraulic booster pump when the car is off, 1540 Farads!..perhaps it got drained. See it here

http://www.mynissanleaf.com/viewtopic.php?f=8&t=3935&hilit=farad

Click to expand...

It is not for "hydraulic booster" it is for electric parking/emergency break, it has nothing to do with power brakes...

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That is incorrect, Herm is correct. The caps are used as an emergency backup for the electric brake boost for the main brake system in the event of temporary power failure, same as the Prius. The caps have noting to do with the electric servo for the parking brake, that would be a pointless feature from a cost basis. The caps are a emergency safety feature for assisted braking.

camasleaf said:

After reading about the issue in the forum, yesterday I believe I noticed/heard/feel the clank in the brake pedal. I was in the garage, so there was no room for tests. I turned it off, with the foot off the pedal. Waited about 10 seconds and started again (press the pedal then the button) without any clanking and the brake worked fine when car was put in reverse. No parking brake was applied at all. I believe I had the driver door open when I started the car first time.

Click to expand...

I'm not sure whether we are talking about the same thing, but I feel it two or three times a week. For me the primary impression is more feeling a clank than hearing a clank. It's like the bottom of the rod that the brake pedal is attached to hits a solid piece of metal shortly after I start to depress it. The sensation I have after that is as if the rod then slips off the edge of whatever it hit, and I can depress the brake normally. No, I never hear any scraping noise when this happens.

For me this only occurs when the car has been sitting quite a while - perhaps only after sitting overnight. It never happens when the car is powered up, let alone when it is moving. It only happens when I am about to hit the power button to start up. And if I power back down and try again it never happens a second time. I never use the parking brake at home, and rarely engage Park explicitly, letting power down take care of that.

Ray

Got a reply back from Nissan tech after he looked at my car.
He said that this behavior is by design.
Brake assist system apparently has a sleep mode, it starts activating when you open the door, so if you open the door, take a sit and start a car, you will never notice anything. The problem starts when you open the door and keep it open for awhile (or if you sit in the car without turning it on for a while), the break assist system goes back to sleep mode, and when you start the engine after that you can feel the clunk when the system wakes up and engages. And if you manages to put the car in drive before the system is fully energized, you can have a diminished brake power.

Yes, the age of simple car is over....

UkrainianKozak said:

Got a reply back from Nissan tech after he looked at my car.
He said that this behavior is by design.
Brake assist system apparently has a sleep mode, it starts activating when you open the door

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Get a second opinion before you kill someone..

This sounds bogus, the car should not activate until the brakes are fully operational, no engineer would be stupid enough to do otherwise.

This is happening to me as well and is increasing in frequency.

I press on the brake before starting and after I press the start button the brake pedal depresses significantly farther.

When I put it in reverse or forward without lifting my foot off the brake I have to press as hard as I can to keep the car from moving.

I have to lift my foot off the brake and depress it again before the brakes work normally.

I thought it was just a one time thing at first but it has happened so often that I finally took a picture of the warning lights so the dealer would believe me when I took it in.

I can't reproduce it every time. It seems random other than it seems to be happening with increased frequency.

Reported it after the first two times and took it to dealer. Said they could not find anything. So I started to record when it happened. Logged over 20 + times.

The last time it happened I was in my garage. Did not want to go through my garage door so I turned the car off.

I restarted the car without lifting my foot off the brake. All the warning lights came on and I could not shut off the

car or put it into gear. "frozen" Left the car on in my garage all day until I came home that evening.

At some point it turned itself off. Had the car towed to dealer.

If this happens to you, the fastest way I found to stop the car is to push the button which puts the car into neutral.

The dealer and the Nissan engineer rep have not been able to reproduce it that I know of. I'm getting the impression that they don't believe me.

Here are two pictures with the warning lights on the upper and lower dash displays and the car in Reverse.



UpperWarningDispaly by mfrptca, on Flickr


LowerWarningDisplay by mfrptca, on Flickr

You can see the BRAKE warning light is on and the yellow brake warning light (the one with the exclamation point) is on. According to the manual in section 2-14 the yellow brake warning light comes on this means that the regenerative and/or the co-operative brake system are not working normally. It says if the BRAKE light is on as well the you should stop the car immediately.

This doesn't sound like normal operation to me. This seems dangerous to me as well.

leaf said:

I restarted the car without lifting my foot off the brake. All the warning lights came on and I could not shut off the

car or put it into gear. "frozen" Left the car on in my garage all day until I came home that evening.

At some point it turned itself off. Had the car towed to dealer.

Click to expand...

Regarding the above behavior, is it the same as if you push power w/o stepping on the brake? (In the absence of malfunction) When one normally does that, you'd end up in ON mode, where it's normal that all or virtually all warning lights are on (see pages 2-13, 5-8 and 5-9 of manual).

The equivalent on Priuses is IG-ON and on most cars w/o push-button start system is to turning the key from OFF to ON but not to START to crank the starter.

It almost sounds like one problem (of several?) could be a bad brake light switch. Altimas (some, both regular and hybrids from 2007-2010) had this problem, covered by NTB10-139. That could also keep you from shifting out of park.

If the car's frozen, what happens if you press and hold the power button or press it 3 times, rapid fire? Does it shut off? That's the emergency shutoff mentioned on page 5-9.

It also sounds like a safety complaint filed at http://www.safercar.gov/" onclick="window.open(this.href);return false; is warranted. Maybe it'd be better once the cause is determined.