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Discussion Starter · #1 ·
From delivery day 1 I have been experiencing phantom braking while using ACC where (I’m assuming) the truck interprets oncoming traffic in the left lane as a slower vehicle ahead I’m the truck’s lane, causing it to slow down precipitously for a fraction of a second or longer. Anyone else?
 

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R1T
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I did experience a braking event yesterday while on ACC with no other cars around me. Was very strange, but that was the first and only I've had after a couple months of ownership.
 

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I've had this a few times as I approach an under/overpass that has a significant shadow cast on the roadway.
Same, I've only ever used ACC on the highway and on several occasions I've had the vehicle apply the breaks when approaching an overpass. I think it might have something to do with the reflective film they put on the signs that typically hang on the side of the overpass that the lidar/radar is getting tripped up on.
 

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Had it happen one time on the Freeway. ACC on. A truck was passing on my right and it just slammed on the brakes. When I touched the brake pedal since I didn't know what was going on, it disengaged from braking.
 

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Yikes. This is the same phantom braking that afflicts the Tesla. In fairness, used to afflict the Tesla. It's been eliminated with the last couple updates.

Does Rivian have a way for the vehicle and/or owner to report issues and time stamp them so Rivian can see exactly what caused the unnecessary braking?
 

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Discussion Starter · #7 ·
I opened a case today about it. Support always asks for a timeframe when “whatever” happens, so they are definitely looking at the logs to correlate events.
 

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I opened a case today about it. Support always asks for a timeframe when “whatever” happens, so they are definitely looking at the logs to correlate events.
One easy way to help Support find this in logs is to momentarily activate the emergency flashers. I was told to do this when we were trying to diagnose another issue...
 

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Tesla has been struggling with this issue since day one. It's a really odd thing, sometimes seems very obvious why it might happen, other times not. I have a very specific spot on my daily commute where my model 3 would phantom break about 50% of the time, with no good theory on why (no bridges, signs, etc.) I would usually watch out and try to disengage AP before I got there, but would frequently forget and then have it hit me. It's very frustrating when it happens. Tesla has slowly improved this issue over the 4 years of my ownership, and it's only been in the last 6 months or so where it's finally improved to the point where I don't really worry about it anymore.
 

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Sorry, Adaptive Cruise Control.
Thanks! I have realized what it is after posting my reply! :)))

Just adding a couple more cents. Per my feeling Rivian doing those phantom braking more gently, I will say... All my Teslas (X, S, 3) were smashing brakes as crazy almost to a full stop for no reason. Rivian can drop a few (5-7mph) and will drive again as normal.
 

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My Audi etron almost never experiences ‘Phantom braking’ whilst using ACC. In fact it has never rapidly applied the brakes automatically when I’ve been on the highway, it has just slowed the etron a little when a vehicle on either side of it has activated their brake lights.
 

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Yikes. This is the same phantom braking that afflicts the Tesla. In fairness, used to afflict the Tesla. It's been eliminated with the last couple updates.

Does Rivian have a way for the vehicle and/or owner to report issues and time stamp them so Rivian can see exactly what caused the unnecessary braking?
Yes. Turn on your hazard lights - that time stamps the event in your vehicle logs for the support team to investigate.
 

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R1T Adventure Package, Rivian Blue
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From delivery day 1 I have been experiencing phantom braking while using ACC where (I’m assuming) the truck interprets oncoming traffic in the left lane as a slower vehicle ahead I’m the truck’s lane, causing it to slow down precipitously for a fraction of a second or longer. Anyone else?
I have had this, but only when approaching a left turn and there is a vehicle ahead in the right lane or parked (so essentially straight ahead). I have had the same issue with other cars too, however. Sounds like you may have a sensor alignment issue if it is left lane...
 

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From delivery day 1 I have been experiencing phantom braking while using ACC where (I’m assuming) the truck interprets oncoming traffic in the left lane as a slower vehicle ahead I’m the truck’s lane, causing it to slow down precipitously for a fraction of a second or longer. Anyone else?
The phantom breaking on my Tesla is a big problem, so its not just Rivian
 
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