mkjayakumar
Well-known member
In any case those Eco tree caricatures in the dash are useless and in a way stupid. It makes the owners look stupid. Take that and give some real useful information.
Sure, it "can," but there are only certain circumstances where it "does." During those times when the DC/DC converter is not on, charge is being drawn from the 12V battery and its SOC is dropping.EVDRIVER said:If the 12V battery can close the main contactor the DC/DC is on and the car has full 12V.
aqn said:There are four hydraulic channels from the ABS controller (LEAF service manual, pages BRC-214, BRC-215), one to each caliper. I should hope that "bleeding off" of hydraulic pressure is done independently in each channel. Hydraulic pressure being relieved in one channel should not affect the other channels.
But that's not how it works, because pressure is regulated on a per-wheel basis, so there is no reason why the non-slipping wheels would not receive full force. Nowhere did I say or even imply otherwise.aqn said:If fluid is prevented from leaving the master cylinder as soon as one wheel locks up and the ABS activates, then the three remaining calipers will not receive any additional hydraulic pressure and therefore their braking power are limited to the level it was at as soon as one wheel loses traction and the ABS comes on.
Which diagram? 'cause there's lots of them. The colored one does indeed show the operation for one wheel only. This diagram, which appears near the top, shows the entire system:aqn said:The diagram shows one ABS channel for one wheel. Braking and ABS action at one wheel should be independent of the others.
There is no reason to believe that the LEAF uses an open system, so I fail to see what relevance that has with the issue. Using the terminology on the pages you linked, the LEAF has every indication of using a closed, non-integrated system.aqn said:Also, that diagram shows a "closed ABS system" where a pump maintains hydraulic pressure in the affected hydraulic path. In an open system, the affected wheel simply has its pressure bled off into a reservoir. "A disadvantage of the open systems is that the brake pedal will drop during a long ABS stop as fluid flows from the brake lines."
I can't see that happening, because there is no place for the fluid to go. The ABS reservoir is, again, tiny and already full of fluid under normal operation. We're talking a thimble-size amount of fluid. There is no return path to the master cylinder except flowing back up the same tubing that is supplying braking pressure in the first place.aqn said:I can certainly see how a software bug, or sensors malfunctioning, can cause all four channels to activate, bleeding off hydraulic pressure from each channel back into the ABS reservoir and/or back into the brake fluid reservoir, the net result being the brake pedal sinking to the floor. (I have not researched the service manual so I do not know whether the LEAF has a return path for excess hydraulic pressure back to the brake reservoir.)
The fact still remains that the OP reported the brake pedal moved all the way to the floor. Twice. SOMETHING allowed for that to happen. The problems with the car seem to have been resolved by making an electrical change and no mechanical failures have been identified.Smidge204 said:There is no reason to believe that the LEAF uses an open system, so I fail to see what relevance that has with the issue. Using the terminology on the pages you linked, the LEAF has every indication of using a closed, non-integrated system.
Which is upsetting, since it doesn't add up. Either the original account was wrong, the service manual and all other available information is wrong, or the real underlying problem still exists. According to the original story there were two incidents roughly a month apart, so it's possible it's behaving itself for now. I do sincerely hope the problem is fixed but I just can't convince myself it's solely an electronic problem.RegGuheert said:The fact still remains that the OP reported the brake pedal moved all the way to the floor. Twice. SOMETHING allowed for that to happen. The problems with the car seem to have been resolved by making an electrical change and no mechanical failures have been identified.
Having low-voltage during the boot up of the electronics could cause problems that full-voltage later doesn't correct.EVDRIVER said:If the 12V battery can close the main contactor the DC/DC is on and the car has full 12V.
oscar said:Maybe this is another indicator I can monitor in next few months. If the clock is correct on display as the navigation clock. I can then use the clock as my indicator for my 12V battery running low.
oscar said:Pick up the car this morning. Once started the Leaf mileage reading show 105 miles on display. I’ve notice the brake felt different in a way that it felt stronger not relax feel as before. I drove the car home and measure the voltage and new battery reading 12.31 volts. Anyway I will do more testing on uneven pavement testing in next few days. Hope all my problem is resolve due to low 12V battery.
Welcome, Nissan support team, this is great to see!NissanSupport said:Hey, Oscar. We sent you a PM earlier today following up on this. Please let us know if you received it. Thanks!
DTB said:I have had a few similar experiences with this brake issue, but nothing quite so dramatic. I've noticed that it seems to happen if I keep my foot on the brake pedal for several minutes with the car off and then start the car and switch to reverse without taking my foot off the brake pedal. The car will start to roll despite what would normally be sufficient pedal pressure. Pushing harder causes the pedal to drop further than normal (not all the way to the floor but the feeling is a bit disconcerting). I had to apply more pressure than I usually would in order for the car to stop rolling however a quick pump of the brake pedal and everything returned to normal.
surfingslovak said:Welcome, Nissan support team, this is great to see!NissanSupport said:Hey, Oscar. We sent you a PM earlier today following up on this. Please let us know if you received it. Thanks!
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