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Recall affecting braking smoothness/cruise shutoff/downhill lurching


MacGyver
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I don't even know the # or whatever, but it has definitely improved the smoothness of braking- just before they fixed mine, it would LURCH badly when braking on a downhill or when braking and turning off the cruise control, as if the brake pedal had to travel so far to activate the switch that cut off the cruise control that you would simultaneously be braking while the engine was still trying to pull the car forward, then a bit more pedal travel would cut cruise and thus engine power, resulting in a LURCH.

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I find our cmax will lurch when going down hill and coming to a slow/stop when it switches from ICE power to electric. I wonder if this recall would be related to this and would be glad to know the number so I can look into it at dealer. It is quite noticeable as you brake to slow and it switches from ICE power to EV when going down hill. I will be keeping my eye on this thread to see if any more info come up or even if others have noticed this lurching.

 

Cheers,

 

Bruce

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  • 2 weeks later...

I have a very consistent case of brakes grabbing just before I stop. I believe it's condensation-related as it only happens when the car is cold and it's either raining or misty. It seems as if the rotors are below ambient temperature, so they condense water vapor. When braking for a high regen score, you're not using the mechanical brakes. Eventually the car comes to a stop, and without motion, there is no regen, so how does the car remain stopped?

 

Brakes.

 

I think I'm sensing the moment when regen braking transitions to mechanical brakes at rest, as I can still get a 100% score, but it's darn hard to stop smoothly. Once the rotors warm up, the grabbing is gone.

 

Anyone else seeing that?

 

HAve fun,

Frank

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I have a very consistent case of brakes grabbing just before I stop. I believe it's condensation-related as it only happens when the car is cold and it's either raining or misty. It seems as if the rotors are below ambient temperature, so they condense water vapor. When braking for a high regen score, you're not using the mechanical brakes. Eventually the car comes to a stop, and without motion, there is no regen, so how does the car remain stopped?

 

Brakes.

 

I think I'm sensing the moment when regen braking transitions to mechanical brakes at rest, as I can still get a 100% score, but it's darn hard to stop smoothly. Once the rotors warm up, the grabbing is gone.

 

Anyone else seeing that?

 

HAve fun,

Frank

Yep, I am seeing that on my energi.

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I don't even know the # or whatever, but it has definitely improved the smoothness of braking- just before they fixed mine, it would LURCH badly when braking on a downhill or when braking and turning off the cruise control, as if the brake pedal had to travel so far to activate the switch that cut off the cruise control that you would simultaneously be braking while the engine was still trying to pull the car forward, then a bit more pedal travel would cut cruise and thus engine power, resulting in a LURCH.

I have experienced this twice...and MacGyver would know this road...when Kannan meets the PCH, there is a long a$$ downhill till you come to a stop at the PCH. Kanann is long enough to full charge the battery...and this is what I suspect happens..when the battery is full, the "extra" grip by the regen component seems to have gone and you only have the more traditional gas-engine brake. You'll know this brake feeling when you cannot charge anymore. Anyway...I had this feeling and as I came to a stop, it lurch a wee bit - unsettling but I figure that was just the brakes-only doing that.

 

I get this same brake feel when going down the longer a$$ Sherwin grade. No lurch really as I was still cruising at 70 mph.

 

At times like this, I wished I had the extra capacity of the Energi...it s*cks to lose all that regen with the battery as full as it gets. Ugh.

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It's a sudden grab, all right, but from 2 mph to 0. I might never have noticed if not for a practice of releasing the brake as the car comes to a full stop.

 

And the key bit is moisture - not wet, not dry, moist. In this week's cold, it's not present. Once the brakes warm up, it's not present. I only see it when driving a cold car in a condensing environment.

 

Have fun,

Frank

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