Started getting random system faults when using cruise control/driver assistance

[schlosrat]

I’ve tried the soft reset, but will try the hard reset too. But honestly this sounds like a prevalent issue. I’m guessing a poor electrical connection somewhere.

If by soft reset you mean the one that resets the infotainment part of the system, I suspect that would not be likely to help, as this functionality is not part of that system. OTOH, if it does help, that would certainly be interesting.

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[zefram47]

Haven't had it happen on the current update with ACC, but two updates ago I was getting an ACC fault with screens freezing while navigating a route and Driver+ engaged. The screens would reboot and then it would work again. But I haven't had that since the latest update, 2025.26.01.

Now, while towing a car hauler trailer this past week, I was getting dumb-cruise failing randomly. It did it many times over the 1000 mile roundtrip and was super annoying. Each time I could re-engage dumb-cruise, but it could be anywhere from 15 to 40 miles before it would kick off. I captured diag logs for two such events, but haven't reached out to Rivian yet.

 

[Calypso]

I had similar experience as @zefram47 . Was towing cross country this week and dumb-cruise would randomly shut down. I was at Rivian Service today and forgot to mention it because of another issue we were addressing.

 

[DD4ST]

Yea, the infotainment reset. and it had no effect.

 

[Calypso]

Picked up my R1T from the service center today and asked a lead tech about the dumb-cruise shutting down. He said they are aware of a bug that crosses Driver+ and dumb-cruise that seems to be causIng it. He expects a future software update to address.

 

[DD4ST]

Picked up my R1T from the service center today and asked a lead tech about the dumb-cruise shutting down. He said they are aware of a bug that crosses Driver+ and dumb-cruise that seems to be causIng it. He expects a future software update to address.

Interesting. Since I wasn’t having this issue until somewhat recently, I wonder if it was a software update that caused it.

 

[ciderarchitect]

My 2023 QM R1T has been doing this for a few months now, and was especially annoying on our 3,900 mile road trip in July. I finally reported it to Rivian and am currently scheduled for a service appointment in five weeks. Since the service center is five hours away, I sure hope they fix it with a software update before then.

 

[topracer]

I believe some owners have reported here that their vehicles are running stock setups (without Comma.ai). I'm curious if we can differentiate between reports from owners never installed Comma versus those using Comma.ai, to help with troubleshooting.

 

[pointless]

I’ve seen it without Comma. Haven’t seen it yet in limited Comma usage.

 

[DD4ST]

As the OP, I am running stock. No Comma.

 

[RivianRocks25]

As the OP, I am running stock. No Comma.

As a data point. 23 R1S QM. I had it on ACC before installed comma, started about July 10th. Installed Comma on July 19th and still getting system fault with Comma. Symptom no different before and after comma: beeps, system fault text on screen and cruise disengaged, can reengage right away. Happens very randomly. Reported back in early Aug and Rivian pushed the latest update (don't have Connect+ so was waiting for update). Seemed better. But has done it again. Maybe once every hour.

PS, Comma kicks a#&! In a 3.5 hr drive on 2 lane state and county roads, had to touch steering wheel for 70 seconds total.

 

[josh0]

It’s just anecdotal, but I was experiencing this issue, and was told by service that it was a firmware problem and would hopefully be resolved in a future update. However after discovering and clearing some debris that rodents had collected in a cavity hidden behind the frunk bin, the problem went away and has not (yet) returned. My theory is that the debris was restricting airflow, leading to some component overheating.

 

[DD4ST]

I garage my R1T. No debris at all. Happened again today on dry, straight pavement, no cars in front of me.

 

[AgentOfEntropy]

OK, I get this too (see: https://www.rivianforums.com/forum/threads/acc-system-fault-punted-by-service-center.50775/). My Gen1 R1S QM/L is currently at the service center where they installed 2025.26.01, and say a better fix is coming in 2025.34. I'm somewhat skeptical as I've had the issue persist across several software updates. I guess if it's a software issue, and they're going to fix it, great. That said, I didn't have any problems until my return from CO, and I didn't do any software updates in CO, so it's not like the software changed to start the problem.

It took nearly 2 months to get in to the service center, then 4 days for them to pull it into a bay, then a few hours to do an update and kick it out again. So I feel they're overwhelmed and they're just trying to free up a bay / tech to work on their backlog.

 

[Gigabit]

On a recent 3 hour drive, I had the ACC abruptly cancel, "Adaptive Cruise Control Cancelled: System Fault Detected" shows on the dash, happened randomly and four total times on the entire round trip. All stock Dual Motor R1t, no Comma Installed.

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