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Joined: Fri Sep 15, 2017 8:06 pm
Delivery Date: 18 Mar 2018
Location: Dallas TX

2018 Leaf Loosing Brake when road has bumps / pot-holes?

Tue May 08, 2018 10:35 pm

I have encouted this couple of times now during 2000 miles of usage. Both times this what I experienced. Was driving at around 45MPH. Apply medium brake enough to stop in about 200ft from 45MPH, while applying brakes if a wheel go over a some bumps (of around 1 inch high) suddenly you will find the car moving without brakes, and brake padel dropping about 1 inch. You need to press hard on padel to gain control / brakes again. At one time I saw a message on dash which quickly disappeared. I think it read "NOT AVAILABLE". (I may be wrong it may have had additional words, I couldn't read this as I was in a panic and applying brakes). It is possible, that REGEN brake give up due to bad road condition and brake pedal dropped down.

I think you loose about 1 second without brakes before you gain brakes back, which could end up in an accident ? This is a safety concern for me. I took car to dealer, and they said everything is normal. It is not easy to reproduce this condition either.

Anyone else had similar experiance? Would like to know?
2018 SL ; 03/18 Delivery ; Dallas TX ; @10k Mile ; SOH=94.83,AHr=109.47,Hx=109.12

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Re: 2018 Leaf Loosing Brake when road has bumps / pot-holes?

Tue May 08, 2018 10:48 pm

This is the ABS in action. It's disconcerting, but all Leafs do it, and all Priuses, at least from the Gen III on, and it isn't as dangerous as it seems. They just have it programmed a little aggressively. There is already a topic or two on this.
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Re: 2018 Leaf Loosing Brake when road has bumps / pot-holes?

Wed May 09, 2018 6:22 am

When the traction control kicks in, regen braking disables. This is how all vehicles with regenerative braking work. There are lots of posts with the Prius because that was many people's first insight into regenerative braking driving.

What you're feeling is not a loss of braking. It is a loss of deceleration or jerk. Humans just suck at feeling this, but very easy to see if you have accelerometer data.
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Re: 2018 Leaf Loosing Brake when road has bumps / pot-holes?

Wed May 09, 2018 6:40 am

This is not a problem, but the high tech braking computer doing its job.

Going over bumps really makes the computer go crazy because the traction control engages.

In the winter you can play with it on ice to see how it works.... just stomp your foot on the brake and hold it. and feel the pumping action.

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