Brakes Fail upon Powering On

[bobkart]

I had problem very similar to yours on a 2015 Leaf. See below the parts replaced and their cost I have found by part number on the web.
Hopfully, parts and labor passed on warranty in my case.

DTC U1000
DTC U110D
DTC P3195
DTC U1008

https://drive.google.com/file/d/1wsvIb2jQROUypMBkZ5hOEvQ3TiEn0wQU/view?usp=sharing

Good luck!

Thanks for that data point. I heard reference to some of those items today at the dealer . . . here's that story.

I paid $192.57 for the dealer's diagnosis. Something about replacing Intelligent Braking System modules and wiring harness ('mysterious short in the harness'). I haven't looked over the estimate yet, but the service advisor says it comes to ~$6K. Strongly advised not to drive it, with repeated questions along the lines of what do I want to do and do I have a tow lined up. I just wanted to settle up and get the car back, as I had a plan of attack.

Was all ready to go through the DTC Reset and battery disconnect/reconnect procedures. But the car fired right up (was on their L2 EVSE and was fully charged). The 12V battery had obviously been disconnected/reconnected. No dash icons other than one for Air Bag (which usually goes away when someone is sitting in the passenger seat).

I drove straight to Midas for a 12V battery load test. They say it failed the test, could only provide 238 amps (less than half the rated value). I'll be reaching out to Ohmmu soon. I haven't checked the DTCs yet.

 

[Thekuai]

I think the load test is irrelevant for electric vehicles. You only need a very small amount of amps to engage the HV coontactors and the computers. You just need good voltage. Load tests are for gas cars with starters. It tests cranking ability which is the hardest task for gas 12v batteries. In fact you will often see CA or CCA ratings for batteries (cold cranking amps)

Leaf batteries are group 51r which are among the smallest, smaller than even Honda civics.

 

[LeftieBiker]

I think the load test is irrelevant for electric vehicles. You only need a very small amount of amps to engage the HV coontactors and the computers. You just need good voltage. Load tests are for gas cars for the starters. It tests cranking ability which is the hardest task for gas 12v batteries.

Leaf batteries are group 51r which are among the smallest, smaller than even Honda civics.

The load test will show whether or not the battery can provide the 10 amps or so needed to start the car. That's much less than a starting motor needs, granted, but if the battery shows 12+ volts but can't cough up those 10 amps, the car won't start. That modest drain is enough to cause a sulphated battery that will still put out 12 volts to drop well below that voltage.

 

[Thekuai]

I think the load test is irrelevant for electric vehicles. You only need a very small amount of amps to engage the HV coontactors and the computers. You just need good voltage. Load tests are for gas cars for the starters. It tests cranking ability which is the hardest task for gas 12v batteries.

Leaf batteries are group 51r which are among the smallest, smaller than even Honda civics.

The load test will show whether or not the battery can provide the 10 amps or so needed to start the car. That's much less than a starting motor needs, granted, but if the battery shows 12+ volts but can't cough up those 10 amps, the car won't start. That modest drain is enough to cause a sulphated battery that will still put out 12 volts to drop well below that voltage.

Yes but he said he took it to midas and they said it provided 238 amps, which is more than enough. I doubt 12v is the issue. His intelligent brake controller failed just like many of us here and its an expensive fix. My abs actuator was replaced as well.

 

[bobkart]

His intelligent brake controller failed just like many of us here and its an expensive fix. My abs actuator was replaced as well.

Thanks for your input. I get that EVs don't need to supply the same high current as is needed to start ICEVs. Still, if whatever battery you have isn't up to the demands that the LEAF booting up puts on it, these symptoms can arise. Ideally there's a test that can make that determination, but I suspect there's a lot of variability as to what that requirement is, explaining the difficulty often seen in reproducing the symptoms caused when the battery doesn't measure up.

I'd be interested to hear whether you think my intelligent brake controller having failed would still allow me to drive the car normally. Not a snide question, just trying to understand if there is such a failure mode. Because it's working as well as it ever has, from all the indications. Regen started at zero bubbles (was at 100% SOC), then gradually the bubbles appeared as the charge wore down on the way to Midas. Lifting off of the accelerator continues to do the same thing it did before this failure (slow the car down and light up Regen bubbles). Light braking will move deeper into Regen (I think, will check that again more closely later today).

I checked the DTCs. There's one that won't go away with just the Reset DTC of Leaf Spy Pro (besides the AIR BAG code, which could also be due to 12V flakiness):

Just after the Reset DTCs it rereads them, and the code is gone then, but on a refresh it comes back. I've yet to go through battery disconnects/reconnects to try harder to reset it (and probably won't until the end of the month, as I like to accumulate my stats on a per-month basis).

 

[ydrape]

Do you hear this noise when you press the brake pedal?

https://www.youtube.com/watch?v=3SCwORR3qbQ

If you can't get rid of this noise by clearing the DTC, the problem is persistent and render the car hazardous to drive in my opinion.

Nissan know very well this problem and has proceeded to a recall. You may try to have the car repaired at Nissan expense.

 

[bobkart]

 

[bobkart]

Do you hear this noise when you press the brake pedal?

If you can't get rid of this noise by clearing the DTC, the problem is persistent and render the car hazardous to drive in my opinion.

Nissan know very well this problem and has proceeded to a recall. You may try to have the car repaired at Nissan expense.

Hi again, that's the video I snagged a dash image from to show the lit icons in an earlier post of mine (thanks!).

Yes, that's the noise I was getting when the failure occurred. All is well now from a behavior standpoint; I just took another trip, and Regen works as expected, including increasing the bubbles on a gradual downhill by lightly applying the brakes.

 

[Thekuai]

His intelligent brake controller failed just like many of us here and its an expensive fix. My abs actuator was replaced as well.

Thanks for your input. I get that EVs don't need to supply the same high current as is needed to start ICEVs. Still, if whatever battery you have isn't up to the demands that the LEAF booting up puts on it, these symptoms can arise. Ideally there's a test that can make that determination, but I suspect there's a lot of variability as to what that requirement is, explaining the difficulty often seen in reproducing the symptoms caused when the battery doesn't measure up.

I'd be interested to hear whether you think my intelligent brake controller having failed would still allow me to drive the car normally. Not a snide question, just trying to understand if there is such a failure mode. Because it's working as well as it ever has, from all the indications. Regen started at zero bubbles (was at 100% SOC), then gradually the bubbles appeared as the charge wore down on the way to Midas. Lifting off of the accelerator continues to do the same thing it did before this failure (slow the car down and light up Regen bubbles). Light braking will move deeper into Regen (I think, will check that again more closely later today).

I checked the DTCs. There's one that won't go away with just the Reset DTC of Leaf Spy Pro (besides the AIR BAG code, which could also be due to 12V flakiness):

Just after the Reset DTCs it rereads them, and the code is gone then, but on a refresh it comes back. I've yet to go through battery disconnects/reconnects to try harder to reset it (and probably won't until the end of the month, as I like to accumulate my stats on a per-month basis).

It will still allow you to drive normal otherwise. The brake will still somewhat work with increased effort and pedal travel. You will just look like an amateur

 

[Thekuai]

Do you hear this noise when you press the brake pedal?

https://www.youtube.com/watch?v=3SCwORR3qbQ

If you can't get rid of this noise by clearing the DTC, the problem is persistent and render the car hazardous to drive in my opinion.

Nissan know very well this problem and has proceeded to a recall. You may try to have the car repaired at Nissan expense.

Is the recall released yet? I paid out of pocket and I'm wondering if I can be refunded

 

[ydrape]

Your estimate is in the order of the repair made under warranty for my car.

If you can stop the car without having the bad noise, your problem is probably in the category «Intermittent».

You don't have to pay for repairing a defect for wich Nissan has aknowledged and proceeded to a recall (in Canada).

I think the recall was also made in USA.

Be safe!

 

[bobkart]

It will still allow you to drive normal otherwise. The brake will still somewhat work with increased effort and pedal travel. You will just look like an amateur.

Then it looks like my intelligent brake controller hasn't failed. There's no detectable change in braking behavior after getting the car back, including no increased effort or pedal travel. I think the last 'proof' is the additional Regen bubbles I can get on a gradual downhill slope by applying light brake pedal pressure . . . I just got back from confirming this to be the case.

 

[bobkart]

If you can stop the car without having the bad noise, your problem is probably in the category «Intermittent».

Agreed. But that leaves out the root cause of the problem (intermittent or not). From what I've read in this (and other related) threads, a failing 12V battery can trigger the problem, or at least symptoms of it. CANBUS flakiness brought on by a failing 12V battery can lead to DTCs that suggest the ABS (or Intelligent Brake Controller) has failed, when it actually hasn't. Distinguishing between actual failure and only apparent failure is key, and my position at this time is that, if at any time the ABS/IBC can be shown to be functioning, that strongly suggests ('proves'?) that the part hasn't actually failed. Of course I mean 'failed' in the sense that the state can't be reversed back to 'not failed' except by repair or replacement of the part in question. I welcome counterarguments to that position, as it's not something anyone would want to be wrong about.

 

[GerryAZ]

Bobkart,

You should be fine with a 2016 (with a new 12V battery). A weak 12V battery will not maintain sufficient voltage during the startup process to keep all of the control and communication modules functioning properly even though it may not test really bad. The 2015's did have some intelligent brake controller issues and I eventually had mine replaced (under the aftermarket extended warranty that I purchased when I bought the car) after getting tired of periodically resetting the DTC's and disconnecting/reconnecting the 12V battery to restore normal operation. It eventually got to the point of happening at least once a month before I had the intelligent brake controller (includes the master cylinder) replaced. I saw the dealer invoice that was close to $3,000 so the aftermarket warranty paid for itself.

Note for reference: The hydraulic brakes still work without electric assist, but the pedal will get close to the floor (may feel like it is on the floor because the pedal becomes really hard to press) and require much higher effort without assist. Also, there was a recall on the 2015 intelligent brake controller that was related to cold weather (just a software/firmware update).

 

[ydrape]

Is the recall released yet? I paid out of pocket and I'm wondering if I can be refunded

You can check here.

https://www.nhtsa.gov/recalls

 

[bobkart]

You should be fine with a 2016 (with a new 12V battery).

Great news; thanks Gerry!

 

[BradLeafOwner]

Bobkart,

I just had the exact same problem show up on my 2014 Leaf this week.
Dealer gave me the same $6000 quote for replacing the brake control unit and harness.
They said everything's up to date recall-wise so there's nothing to be done there.
Mine's long out of warranty and not worth this expense, so I didn't have the work done.

The dealer cleared the DTC codes and everything has worked perfectly for the last couple of days, but I'm worried about getting stranded if it happens again.

Did you ever end up having those parts replaced or did you figure out some other solution or a work-around?
I recently replaced my 12V battery, so I don't expect that to be the problem, but it sounds like something I should check.

 

[bobkart]

Did you ever end up having those parts replaced or did you figure out some other solution or a work-around?
I recently replaced my 12V battery, so I don't expect that to be the problem, but it sounds like something I should check.

Hi Brad, there has been no recurrence of the symptoms of this problem. Most likely some odd/fluke power glitch confused the system. Improving your 12V battery reliability (as you've done) is a good step. My feeling is that, unless there really is a hardware problem, a subsequent appearance of this problem can be cured by briefly disconnecting the 12V battery (EDITED to add that DTCs may need to be cleared also). Since I had that problem I've added quick-disconnect capability on the 12V battery negative terminal.

I think the vehicle is borderline drivable when in failure mode. Probably not at freeway speeds but one might crawl home on surface streets, if that's an option. Still, I'd be prepared to disconnect the 12V battery as a first resort.

 

[bobkart]

In addition to the above, I bring LeafSpy Pro (cellphone & dongle) everywhere, in case resetting DTCs is needed to get past the problem (after a brief disconnection of the 12V battery).

If you don't care to add a quick-disconnect capability to the 12V battery negative terminal (it can cause problems if done poorly), a 10mm open-end wrench will do.

 

[BradLeafOwner]

That's great to hear, Bob. I hope my experience is similar and that it does not become a recurring problem.
Thanks for your suggestions and prompt reply!