Lost braking 3 times in the past 5 months on my 2015 Leaf!

[LeftieBiker]

The 2015 Leaf should have a foot-operated mechanical parking/emergency brake.

[cwerdna]

GerryAZ: Ouch! Hopefully you'd filed a safety complaint w/NHTSA at www.safercar.gov. Might help others to do so, if you haven't already.

ctesti: Might help to do the same if that ends up being the fix for you too.

The brakes still worked (without power assist) so I saw no reason to file a safety complaint. I posted this issue in several other threads over the years that mention loss of brakes. Again, I always had braking capability although the pedal effort was high when the CAN bus communication failed.

Cars have been recalled for loss of braking power assist. Google for recall for loss of power assist braking. If you Google for recall for loss of power assist braking -camry, you'll find some more.

So, given that, it seems worthy of reporting to NHTSA. Might lead to an investigation which might lead to a recall.

[ctesti]

Cars have been recalled for loss of braking power assist. Google for recall for loss of power assist braking. If you Google for recall for loss of power assist braking -camry, you'll find some more.

So, given that, it seems worthy of reporting to NHTSA. Might lead to an investigation which might lead to a recall.

Agreed!

Just got off the phone with the Nissan Dealer... they are having trouble to get the extended insurance claim approved. Looks like the dealer is asking for $9,000 to replace the Intelligent Brake Assist, including 25 hours of labor!! That's pretty much the price I paid for that Leaf 2 years ago

[GerryAZ]

25 hours labor is excessive. The work is similar to replacing a brake master cylinder on a conventional brake system with a little extra time to unplug/plug electrical connectors and for calibration with Consult 3+. My dealer also had trouble getting the extended warranty to agree to the repair, but I just drove the rental car that the warranty company was paying for until they came around. The car was ready in less than a day after authorization and receipt of new part. I will try to report the issue through NHTSA if I don't need to look up exact dates/mileage of the intermittent failures.

[nlspace]

There have been hundreds of posts on this forum and other EV and car forums by folks with weird issues that were caused by weak or old batteries. Even brand new batteries from the dealer or off the shelf at auto parts stores--they are sulfated from sitting on the shelf for an extended time during these pandemic times. That is why i suggest you do a 15 second load test at 150 Amps to check and verify the condition of the "new" battery. Even better is also do a capacity test.

You have made 2 assumptions: that the dealer would check the new battery before installation, and that it is "good" just because the OCV is 12.7V. i have bought 4 new 12V batteries over the past year and none of them were fully charged even though they read 12.7V. They all needed to be charged up to 14.4 to desulfate the plates and reach a full charge level, after which the new voltage was 12.8 to 13.2V. 12.7 is not a full voltage charge of a new battery.

Once the possiblility of a battery issue is completely ruled out by verified performance, then you can address the CAN buss issue, if it still exists.

i would consider exercising the brake system by driving fore and aft in the driveway, or slowly around the block on a side street. Accelerate up to 15-20mph, then hit the brakes, then let off; drive around and do about 50 cycles. Listen for the motor actuator squealing or any other weird noises. The motor advances the ball screw under braking, then retracts when you let off. If the car has set for awhile, then the brake motor actuator may have some surface rust, debris or corrosion that needs a good work over to get back to shape. Look at all the bearings, springs and sliding surfaces that could contribute friction to the actuator--it's a complicated piece for sure. Good luck on getting it sorted out.

[GerryAZ]

My issue was not caused by a low 12V battery. It happened a few times before the OEM battery failed and then a few more times after I installed a new deep cycle AGM (yellow top Optima) battery. It never happened for the remaining time I owned the car after the intelligent brake controller was replaced. The Optima battery was also in excellent condition when I traded the car for the 2019.

You made a good point about fully charging new 12V batteries before installation (regardless of the vehicles). I have purchased new batteries for several vehicles in the past few years and each one required significant charging time to reach initial full charge.

[Dala]

Make sure the brake booster firmware is updated to the latest version. Dealership can flash this, should alleviate the issue.

[jjeff]

Make sure the brake booster firmware is updated to the latest version. Dealership can flash this, should alleviate the issue.

I recently had my '13 Leaf into the dealer to fix a recall for the bonding plate and asked them to update the firmware for the brake booster as I'd recently had the brake booster fail during extreme cold and they said it didn't affect my Leaf and they didn't do the update. Now maybe if I'd have offered to pay for the fix? but they didn't ask and as the description of what this update fixed, sounded very much like what I experienced I was kind of bummed they didn't seem to interested in looking into it. Now it hasn't happened since the one time and that cleared after putting my car in a heated garage overnight.

[Dala]

Jeff, start by reading the ECU versions and see if you have the old version or new