Sudden Brake Malfunction While Parked

[btointheeto]

2015 Nissan LEAF. My wife arrived home at about 3:30 pm in the LEAF, with no reports of anything unusual. 10 minutes later she got back in the LEAF to leave, and reported that the brake pedal was making all kinds of weird noise, and some lights were on on the dash. The brake light and exclamation point light are on (though the parking brake is on and I don't plan on taking it off with the weird brake issues going on, so the brake light is of little use maybe).

I checked the 12V battery voltage with everything off and it reads 12.30 volts, but I'm not sure whether that's as useful as it might be on an ICE car.

Here are four short video clips of the sound I'm hearing when I depress the brake pedal to the floor. We have not attempted to take the car out of part. The sound occurs whether the car is in drive mode or standby mode.

Anybody have any ideas? Sorry in advance for the bare feet.

[youtube]https://youtu.be/mHFQVueYcT4[/youtube]
[youtube]https://youtu.be/YP0VDA_1zeI[/youtube]
[youtube]https://youtu.be/shmN3pgshvA[/youtube]
[youtube]https://youtu.be/McWmJ3xJJO0[/youtube]

 

[LeftieBiker]

At that rest voltage the 12 volt battery may or may not be part of the issue. I don't think it's the whole issue, and that noise is not something I've heard or heard described before. You need the error codes, which you can read with LeafSpy Pro and a compatible OBDII port reader like the one in my signature, but I suspect the electric brake booster.

 

[nlspace]

Yes your Aux battery is the cause; 12.3 with everything OFF is nearly a dead battery. How old is it, doesn't really matter--it needs to be replaced. The aux is too weak to release the parking brake mechanism, or drive the motor in the brake master cylinder.

The plates get sulfated over and will no longer pass current; the voltage might read 12 but it worn out.

A lead acid battery must always be kept at full charge or it will sulfate over and die.

 

[LeftieBiker]

Let's hope it's just a weak 12 volt battery! There should be an easy test: charge it for a couple of hours on an external charger with the negative or positive cable battery disconnected to clear the codes, then see if you can operate the brake normally.

 

[LeafNoBueno]

Hopefully this post helps anyone else with similar break failure. I'm getting rid of my leaf unfortunately.

My 2014 Nissan Leaf with 106k miles suddenly started throwing an ABS system light & made a weird noise when depressing the brake pedal.

After the noise going away a couple of times with letting the car sit for a while it permanently started making the noise. Brakes won't work.

Nissan dealer wants 5k to replace the following:

Issue
MULTIPLE DTC'S STORED ACROSS SYSTEMS. FOCUSED DIAGNOSIS ON CAN COMMUNICATION DTC'S. EDB CONTROL UNIT LOST ON CAN NETWORK. INTERNAL FAILURE OF BRAKE UNIT ASSY.

Recommendation
FIRST STAGE REPAIR: REPLACE ELECTRICALLY DRIVEN BRAKE CONTROL UNIT ASSY. CONFIRM BRAKE CONTROL UNIT IS VISIBLE ON NETWORK. ROAD TEST TO DERTIME IF FURTHER DIAGNOSIS IS NECESSARY.

Estimate
$ 4,890.00

I drove the car hard (bought in 2019 with 40k miles) and put some 19" rims on it. Not sure if the rims had anything to do with the abs failure or the constant coasting/gliding I would do to maximize the range.

I would engage the car in neutral when coasting thinking it would give me more range. I also didn't change the breakfluid ever until the mechanics diagnosing the abs issue told me about it. It was pretty good considering the driving I was told. I didn't need to brake much do to Regen.

The AC also went out and my suspension was shot (ran over a piece of plywood on freeway along with LA streets). This car took a beating as have my previous cars but this was by far my favorite and saved me tons of money of gas/maintenance until now.

Definitely going to miss the car

 

[GerryAZ]

That noise is the brake booster and ABS system. It can be caused by CAN Bus communication errors (which can be caused by low 12V battery among other issues). Try reading/clearing DTC's with Leaf Spy Pro, disconnect/reconnect 12V battery, and clear DTC's again (repeat combination of clearing error codes and disconnecting/reconnecting 12V battery until all error codes are clear). Then the brakes should work normally until something happens on the CAN Bus again.

My 2015 did this periodically and displayed numerous errors associated with CAN Bus communication as well as errors directly related to the intelligent brake controller (brake booster). It usually happened after being parked for a short time after being driven. Brakes would still work, but without power assist unless pedal was pressed hard (then power assist would sometimes come on very abruptly). Pedal would go almost to the floor before brakes would take ahold without power assist. I used the above procedure to clear the error codes whenever it happened without incident. It started happening more frequently so I eventually took it to the dealer with the noise present (the look on the service advisor's face was priceless when I demonstrated the brake noise). They diagnosed a failed intelligent brake controller and replaced it under the extended warranty that I had purchased when I bought the car new.

 

[JJoynt]

I just had a similar problem. While on the way home from work Friday night I called and suggested to my wife that we try out a new pizza joint for supper. She agreed and I got hime 5 minutes later and shut the car ('15 Leaf SV) off and got out of the car to greet my doggo. Then a few minutes later we got back into the car and the brake pedal went right to the floor and there was a terrible metal on metal noise.

The brakes reminded me of my mothers 67 Impala which had standard brakes. My Leaf Spy Pro indicated the AUX battery was sitting at 12.3 VDC. Essentially dead! My Aux battery is an Optima AGM ($400) with a 5 year warranty. I was 13 months into the warranty. I took the battery back to where I bought it this morning. They load tested it and it indicated an as found state of charge before they charged it of 55% and 545 Cold Cranking Amps reserve. The original store put it on their charger for an hour and it came up to 13.3 VDC. I then brought it back home and put it on my AMG charger for an additional hour and it came up to 100% or 13.6 VDC.

At this point I reinstalled it and drove around for 5 minutes and shut it off. It all appears to be working well now.

My question to all of the learners scholars on this channel is why did my main brain let that Aux battery get so low? I drive 60km ~40miles a day. and I charge it for one hour a night, every night and put in about 6.4 kW of energy. This just keeps ahead of the my power demand.

I love my Leaf. 94,000 driven since new. Gas at $2.50 per litre. I get 8km/kWh. I pay 9.4 Cents per kWh. So when all of the dust settles I pay about $0.55 per day to drive to and from work. By contrast it costs $135 to fill my wife's MB wagon. That gets her about 400km. It costs me under $5 to drive that far in the Leaf. My total running costs for the Leaf has been $1,175 for 100,000km. For my wife's MB it has been about $17,000 plus 3 x $100 oil changes.... I will have to speak with her about the economics of running her ICE car.

Man did I go off on a tangent or what...? I guess I am rehearsing my speech to her about trading her car in on an EV.

So where was I ????? Charging the Aux battery fixed the issue for me. I will update in a few weeks.

 

[LeftieBiker]

My Leaf Spy Pro indicated the AUX battery was sitting at 12.3 VDC.

Two things here. First, you can't use LeafSpy to tell you the rest voltage of the 12 volt battery, unless maybe you try it in Accessory mode, because when the car is on, the DC-DC converter is on, and that is powering the 12 volt system. The second thing is that this was quite low for a Leaf in Ready mode, for the reason above. If the car was indeed in Ready mode (yellow-green car icon lit), then the 12 volt battery was probably at or below 12 volts, with the DC-DC converter pushing it up from there.

I drive 60km ~40miles a day. and I charge it for one hour a night, every night and put in about 6.4 kW of energy. This just keeps ahead of the my power demand.

This may possibly be the problem, if you leave the car plugged in for hours before and/or after charging. Being plugged in but not charging saps the 12 volt battery, stupidly enough...

 

[GerryAZ]

If Leaf Spy indicated 12.3 volts when you turned the car on (which activates the DC-DC converter), then the battery voltage was probably well below 12 volts before turning the car on. Low voltage on the 12V system will cause CAN Bus communication errors and the brake issue you observed. Disconnecting the 12V battery and then reconnecting a charged 12V battery will clear the CAN Bus communication errors so the brakes and ABS systems function normally. I have been using Optima yellow top (deep cycle) batteries in each LEAF after the OEM failed and have yet to replace one. The one in the 2011 was doing fine when the car was rear-ended and ultimately declared a total loss by the other driver's insurance company (even though it was repairable). The one in the 2015 was doing fine after at least 2 years when I traded the car in on the 2019. The one in the 2019 is only 8 months old, but the 12V battery test report (as part of the annual traction battery report and vehicle inspection performed yesterday) shows resting voltage of 12.62 and 692 cold cranking amperes so it appears to be in like new condition. I have never connected an external 12V battery charger to any of my LEAFs, but I usually discharge the traction battery rather deeply and then plug in to charge fully so the DC-DC converter has ample time when driving and when charging the traction battery to keep the 12V battery charged.

As LeftieBiker indicated, leaving the car plugged in when not charging (such as setting an hour per day on the charge timer and keeping the car plugged in while parked) will cause the car's systems to draw more power than when not plugged in. This will somewhat discharge the 12V battery until you unplug and then drive the car in the morning. Your 60 km (40 miles) per day driving should be enough for the DC-DC converter to recharge the Optima by the time you get home (assuming it is not a bunch of very short trips) so I am surprised that it was that low. The battery voltage shown on LEAF Spy should be about 13 volts while the car is on after it has been driven long enough to fully charge the 12V battery. LEAF Spy should show battery voltage at about 14 volts while the car is on until charging current drops below about 5 amperes (for 2015, threshold for switching from charge to float voltage is different for different model years).

I recommend that you check/clean battery cable connections and especially the negative cable ground connections (the one to the body looks like a cable support clip a few inches from the battery) because something may be causing insufficient 12V battery charging.

 

[LeftieBiker]

If the problem is the OP's charging habits, then the solution is to charge the car once a week for as long as it takes to get a week's worth of charge, not charging an hour a night. Having a shallow charge/discharge curve is a worthy goal, but only if it doesn't cause any problems itself. Even twice a week, for half as long, would be fine - as long as the car isn't sitting around for hours, plugged in but not charging.

 

[LeafNoBueno]

Thank you for all the feedback. My car has been inoperable due to the brake issue since March 2022. The last time I moved it was about 2 months ago to park it at my new place. Any suggestions on independent Nissan Leaf mechanics in California? The 5k repair bill is killing me plus the AC & suspension are out. I drove the car heavy for over 2 years & I hate seeing it collect dust :|

Might just part it out for parts at this point if I can't find a cheaper repair option. Below is the report I received from the dealer.
Concern

Critical
Tow In. Customer States Vehicle Makes A Buzzing Noise When Pressing On Brake Pedal Check And Advise. Customer Notes Vehicle Was A Costa Mesa Nissan But Vehicle Was Not Repaired. Vehicle Has No Brake Pressure. Be Careful When Moving.

Cause
MULTIPLE DTC'S STORED ACROSS SYSTEMS. FOCUSED DIAGNOSIS ON CAN COMMUNICATION DTC'S. EDB CONTROL UNIT LOST ON CAN NETWORK. INTERNAL FAILURE OF BRAKE UNIT ASSY.

Correction
FIRST STAGE REPAIR: REPLACE ELECTRICALLY DRIVEN BRAKE CONTROL UNIT ASSY. CONFIRM BRAKE CONTROL UNIT IS VISIBLE ON NETWORK. ROAD TEST TO DERTIME IF FURTHER DIAGNOSIS IS NECESSARY.

Estimate
$ 4,890.00

[https://photos.app.goo.gl/H4rBdpAdQENjw3PQ7][/img]

 

[alozzy]

Why not just buy a new 12V battery, fully charge it before installing it in the Leaf, use LeafSpy to clear all DTCs, then see if that cures the problem. Minimal cost to do the above and it's all pretty easy DIY stuff.

 

[sigh]

My brake assembly failed last year and I got a used one from a breakers yard Nissan fitted it for around $700. So far so good. Although tonight I heard a couple of brake stutters (pump noise on start up) before I drove home. I checked the DTC codes with Leaf Spy and nothing showing. So hopefully I am still good. This unfortunately is very common on Leaf's which is why you see so many in the breakers yards with front end damage. Clearing codes with Leaf Spy works temporarily until the fail starts happening regularly then its just too annoying. I believe this problem doesn't happen with newer Leaf's after 2017 however Nissan will never say that of course. Guess the new firmware corrects the issues somehow. Question is can you fit a newer part to an older Leaf everyone keeps telling me no.

The most annoying thing is its brakes if it was something else I'd happily stand the costs but the brakes go will little warning making the car dangerous depending on your chance of anticipating it. Pressing the pedal to the floor in heavy traffic and squeezing your ass cheeks together is not a pleasant experience!