I know, I know there are many existing brake threads. However, I searched and have not seen this one yet. I have a 2012 with 44k miles. The intelligent brake module failed and the brakes were engaged on matter whether your foot was in the brake pedal or not! Anyone else seen this?
Them's the brakes - new issue
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DNAinaGoodWay
Well-known member
Could also be the emergency/parking brake is stuck, or just engaged?
Brake Assist will apply brakes in full panic stop mode if you move your foot quickly from accelerator to brake pedal. If Brake Assist engages at higher speeds (50 mi/hr is sufficient), the brakes will stay fully engaged until the car comes to a complete stop. That can be disconcerting. The only way I have found to get the brakes to release before coming to a complete stop is to depress the accelerator pedal. Nissan considers this "normal" and will do nothing to change the brake assist action.
It sounds like either the controller or sensors have failed and it is applying brake assist. Do the brakes release when the car is sitting still or do the brakes remain locked? Since the intelligent brake controller is integrated with the inverter and traction motor controls, I would argue with Nissan and your dealer that the entire system should be covered by the EV power train warranty (5 years or 60,000 miles in USA).
Gerry
It sounds like either the controller or sensors have failed and it is applying brake assist. Do the brakes release when the car is sitting still or do the brakes remain locked? Since the intelligent brake controller is integrated with the inverter and traction motor controls, I would argue with Nissan and your dealer that the entire system should be covered by the EV power train warranty (5 years or 60,000 miles in USA).
Gerry
I did read about brake assist being applied after sudden/hard braking however that was not the case here. My wife left work, started driving and noticed the issue. The car was always applying the brakes even when her foot was off the pedal. Unfortunately she was on a dangerous road and could not stop for a couple of miles until she got to a safe spot. She was driving about 25-30 mph. Flatbed to dealer. Dealer investigated and found the intelligent brake module failed. Also because she continued to drive the rotors and brakes are shot. Odd thing is that there was no warning light. It seems like a serious safety issue. My guess is that this will cause accidents at some point n the future and there will eventually be a recall.GerryAZ said:
Thanks for the advice on drive train approach. I will try that. Cost to fix is thousands!
TimLee
Well-known member
I am a bit surprised that LEAF could manage 30 mph with brakes fully engaged.
I have used the hold the brake and apply acceleration to just the point of movement to try to reduce the grabby brakes of the LEAF. Sometimes helps things for a while.
But I never ran a test to see how fast the LEAF could go with brakes fully applied.
I am a bit surprised the LEAF programming would allow continued vehicle movement with brakes fully applied.
But depending on the failure mode the LEAF software may not have known the brakes were applied.
If that is the case, does appear to be a shortcoming in the LEAF design that it doesn't have a pressure sensor to recognize that the brakes are applied.
As someone who experienced a stuck full throttle on a Lincoln Town Car, which was impossible to slow down to less than about 60 mph even with massive force on the brakes with the throttle fully engaged, vehicle design has been deficient for a long time in allowing full throttle and full braking at the same time.
Toyota's experience is certainly an example of such inadequate design.
Were the brakes fully engaged from the moment your wife left the parking lot, or did the failure occur and the brakes engaged at some point while she was driving? Could make a difference in the understanding of the failure mode.
Good luck with getting Nissan to fix under warranty.
This is just one more of a few LEAF failures that are extremely costly outside of warranty.
Glad I paid for seven year warranty just in case.
But such failures as this, and electric parking brake failure, and traction motor failure; do make me worry about the LEAF maintenance cost after my warranty runs out in three years.
I have used the hold the brake and apply acceleration to just the point of movement to try to reduce the grabby brakes of the LEAF. Sometimes helps things for a while.
But I never ran a test to see how fast the LEAF could go with brakes fully applied.
I am a bit surprised the LEAF programming would allow continued vehicle movement with brakes fully applied.
But depending on the failure mode the LEAF software may not have known the brakes were applied.
If that is the case, does appear to be a shortcoming in the LEAF design that it doesn't have a pressure sensor to recognize that the brakes are applied.
As someone who experienced a stuck full throttle on a Lincoln Town Car, which was impossible to slow down to less than about 60 mph even with massive force on the brakes with the throttle fully engaged, vehicle design has been deficient for a long time in allowing full throttle and full braking at the same time.
Toyota's experience is certainly an example of such inadequate design.
Were the brakes fully engaged from the moment your wife left the parking lot, or did the failure occur and the brakes engaged at some point while she was driving? Could make a difference in the understanding of the failure mode.
Good luck with getting Nissan to fix under warranty.
This is just one more of a few LEAF failures that are extremely costly outside of warranty.
Glad I paid for seven year warranty just in case.
But such failures as this, and electric parking brake failure, and traction motor failure; do make me worry about the LEAF maintenance cost after my warranty runs out in three years.
TimLee said:
She got to work fine. Left work, started the car and began driving. The problem began as soon as she started the car although she did not know what was wrong right away. After a short time she notice the battery was draining quickly, GOM dropping fast and then burning smell from the brakes. At that point she had to find a safe place to stop.
I agree the car software should not allow the car to start or drive if the intelligent brake module fails.
Thanks for the advise.
TomT
Well-known member
Reminds me of Toyota and their saving a few cents by not implementing brake throttle override a few years back...
TimLee said:
TimLee
Well-known member
More than that.TomT said:
Toyota failed to implement other important things, such as interference filtration.
Did Toyota ever fix the problem :?: :shock:
