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Regen dropping out while braking, and now downhill!

SpaceCase

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Twice now I have experienced an event when I am braking and all of a sudden the force from the regen disappears and I have to really push hard on the brakes to stop. The charge/power gauge will also drop to zero. This is with max regen on, and I have verified it is still on after the event and didn't just "turn off".

Quite a scary feeling when the braking of the jeep suddenly "goes weak" when I am slowing at a stop light! Has anyone else experienced this?
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bodhi

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This happened to me for the first time the other day actually, I have only about 600 miles on my 4xe. I was slowing down to take a right hand turn, and I did have my foot on the brakes, and all of a sudden the regen braking was gone, and the pedal was super hard, and I really had to react quickly to avoid an accident. Max Regen was on for me as well, but I didn't notice anything with the charge/power gauge cause I was too busy reacting.
 
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SpaceCase

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I have reached out to @JeepCares Braking failure is a serious issue and I hope it is addressed quickly.
 

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Perhaps this is the reason it has been defaulted to off on start!

I don't see what could cause that other than the transmission going in to neutral. Otherwise, isn't it just magnetic resistance?
 
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I don't see what could cause that other than the transmission going in to neutral. Otherwise, isn't it just magnetic resistance?
While the transmission going into neutral could cause that by disconnecting the very inertia the regenerative braking uses, the transmission is mechanical and probably did not go into neutral and back to drive in just a few seconds. The brakes on the other hand are electronic and computer controlled. Based on the way the brakes acted (had to press HARD) they were not acting like they should.

I tried popping the transmission into neutral and the brakes activated as expected, likely using the disc brakes. I did not have to press HARD.

More than likely we are experiencing a serious issue with the braking system and the way the Jeep computer controls it.
 

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michail

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So the computer thought regen was working and held back on the the physical brakes. That's two things going wrong.

  1. Regeneration stops
  2. Brake system doesn't detect regeneration failure

That's something the engineers need to be on top of!

I'm still not sure what would cause #1 as it's an electromagnetic generator. The only thing I can think of is something physically disconnected. Item #2 is the more serious problem.
 
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So the computer thought regen was working and held back on the the physical brakes. That's two things going wrong.

  1. Regeneration stops
  2. Brake system doesn't detect regeneration failure

That's something the engineers need to be on top of!

I'm still not sure what would cause #1 as it's an electromagnetic generator. The only thing I can think of is something physically disconnected. Item #2 is the more serious problem.
I suppose it could be related to your transmission idea if the clutch for the electric motor disconnected and the vehicle still thought it was regenerative braking...
 

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This happened to me for the first time the other day actually, I have only about 600 miles on my 4xe. I was slowing down to take a right hand turn, and I did have my foot on the brakes, and all of a sudden the regen braking was gone, and the pedal was super hard, and I really had to react quickly to avoid an accident. Max Regen was on for me as well, but I didn't notice anything with the charge/power gauge cause I was too busy reacting.
Sorry to hear that, bodhi. We'd be happy to discuss your current concerns further. Please send a private message with more details.

Kate
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michail

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I suppose it could be related to your transmission idea if the clutch for the electric motor disconnected and the vehicle still thought it was regenerative braking...
Makes sense as to why the brakes were so hard to operate. Still, that's just speculation.

Keep us posted, I haven't had issues but I'm curious.
 

SnB4xe

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A couple of idea come to mind while reading this thread.
If I were a tech with the appropriate scan tool, I would look at the ABS system first. Might have an intermittent fault with a sensor, wiring or connector etc. If any of the ABS sensor go off line, the system will likely drop into a default status which almost certainly disables regenerative braking and possibly also the electrical brake assist for the friction brakes as well.

Could be something totally different as well.....but those are my thoughts.
There may be some saved codes in the system so perhaps the dealer might be able to scan the vehicle and find some data to work with. ???
 

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A couple of idea come to mind while reading this thread.
If I were a tech with the appropriate scan tool, I would look at the ABS system first. Might have an intermittent fault with a sensor, wiring or connector etc. If any of the ABS sensor go off line, the system will likely drop into a default status which almost certainly disables regenerative braking and possibly also the electrical brake assist for the friction brakes as well.

Could be something totally different as well.....but those are my thoughts.
There may be some saved codes in the system so perhaps the dealer might be able to scan the vehicle and find some data to work with. ???
I am planning to go to the dealer, but without a consistent way to replicate the issue it's going to be hard to find the problem. I am planning to spend some time this weekend to see if I can reliably replicate the problem, and document any conditions that may be required.
 

SnB4xe

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I am planning to go to the dealer, but without a consistent way to replicate the issue it's going to be hard to find the problem. I am planning to spend some time this weekend to see if I can reliably replicate the problem, and document any conditions that may be required.
I am in a similar boat. I have an alert or alarm noise inside the cabin from time to time. Reached out to JeepCares and they are trying to help. Unfortunately I am not able to trigger the symptom on demand so taking it to the dealer might prove fruitless.

I will keep trying and see if I can figure out some trick to reproduce the sound and then we can make an appointment with the dealership.
 

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Twice now I have experienced an event when I am braking and all of a sudden the force from the regen disappears and I have to really push hard on the brakes to stop. The charge/power gauge will also drop to zero. This is with max regen on, and I have verified it is still on after the event and didn't just "turn off".

Quite a scary feeling when the braking of the jeep suddenly "goes weak" when I am slowing at a stop light! Has anyone else experienced this?
One thing I'm wondering is what was the battery level when you experienced this? I had a Volt previously and when the battery was full regen braking was not as aggressive as when one or two bars of battery had been used. GM said it was because the regen breaking was producing electricity and when the battery was full there was no place to put the energy. Anyway, just an experience I had on a completely different platform, so probably has no bearing. Good luck.
 
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SpaceCase

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One thing I'm wondering is what was the battery level when you experienced this? I had a Volt previously and when the battery was full regen braking was not as aggressive as when one or two bars of battery had been used. GM said it was because the regen breaking was producing electricity and when the battery was full there was no place to put the energy. Anyway, just an experience I had on a completely different platform, so probably has no bearing. Good luck.
Battery level every time was less than 50%, although I can see why a full battery would be an issue. I assume that's why esave only holds the battery at 95%.
 

cryptyk

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One thing I'm wondering is what was the battery level when you experienced this? I had a Volt previously and when the battery was full regen braking was not as aggressive as when one or two bars of battery had been used. GM said it was because the regen breaking was producing electricity and when the battery was full there was no place to put the energy. Anyway, just an experience I had on a completely different platform, so probably has no bearing. Good luck.
My Tesla does this, too. Regen braking cuts out when the battery is full. It "knows" that and doesn't mess with the braking feel, though.
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