Comma harness issues?

[bryanmtl]

Hey friends,

After a few months of near flawless operation, I've run into a conistent issue where the Comma is seemingly affecting operation of the ADAS unit. A few minutes after engaging, the car complains that the front camera and sensors are unavailable. At first, they'd come back themselves, but now, the only want to get them to work is a full reboot.

Has anyone else had this issue? I wonder if I have a faulty harness? It's worth noting that I have a magnetic mount. I've tried booting up with the unit connected and disconnected. It doesn't seem to have an effect.

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[godfodder0901]

Hey friends,

After a few months of near flawless operation, I've run into a conistent issue where the Comma is seemingly affecting operation of the ADAS unit. A few minutes after engaging, the car complains that the front camera and sensors are unavailable. At first, they'd come back themselves, but now, the only want to get them to work is a full reboot.

Has anyone else had this issue? I wonder if I have a faulty harness? It's worth noting that I have a magnetic mount. I've tried booting up with the unit connected and disconnected. It doesn't seem to have an effect.

Have you bypassed the AXM power? And are you 100% sure it's the comma, and just crappy ADAS software?

 

[Osyras]

There was a thread on this a while back - if i recall correctly it was the harness was pulling power from the IC, and there was a new harness to pull it from 12v directly rather than the IC?

I am not a comma user and going entirely of memory....

 

[pointless]

I’m using a fuse tap, not AXM and have recently been getting an urgent “restart vehicle” error from my Comma 3x. Coincided with Rivian software update. Since Sunnypilot seems to update silently, I don't know if there was a corresponding update.

 

[gerrylum]

I’m using a fuse tap, not AXM and have recently been getting an urgent “restart vehicle” error from my Comma 3x. Coincided with Rivian software update. Since Sunnypilot seems to update silently, I don't know if there was a corresponding update.

I think this has something to do with the ongoing random ACC disengagements issue on the Rivian. I've gotten these a few times and it always coincides with the Rivian's ACC disengaging.

 

[bryanmtl]

The harness and/or the Comma device is really starting to drive me nuts. After re-seating all the connections, flashing the device, I managed to get ~300 miles of driving without the constant front sensor and front camera errors. I thought I was home free.

On the drive home (~4 days later), 280 of the 300 miles, all driving aids (cruise control, front sensor/camera) were disabled.

I finally took a video of the issue. At this point, I'm not sure what to do. It sure feels like a flaky harness to me (I haven't tried bypassing the power, but I do have it hooked up to the ODB2 port). I'm tempted to buy the harness Lukas offers to see if that helps at all.

 

[gerrylum]

The harness and/or the Comma device is really starting to drive me nuts. After re-seating all the connections, flashing the device, I managed to get ~300 miles of driving without the constant front sensor and front camera errors. I thought I was home free.

On the drive home (~4 days later), 280 of the 300 miles, all driving aids (cruise control, front sensor/camera) were disabled.

I finally took a video of the issue. At this point, I'm not sure what to do. It sure feels like a flaky harness to me (I haven't tried bypassing the power, but I do have it hooked up to the ODB2 port). I'm tempted to buy the harness Lukas offers to see if that helps at all.

Post a route with uploaded logs on the comma discord server. It's hard to diagnose from a video. I would also say that removing the AXM power connection on the harness could also potentially help. We know from experience that not only is the AXM very sensitive to power fluctuations in general, but having two systems connected at the same time has the potential to backflow power into both systems which could definitely cause issues.

 

[KJWah]

I would try to remove the magnetic mount out of the equation if you are using a quick release version that has extra usb adapters in the loop. I had/have a quick release magnetic mount an originally used the usb adapters for a quick release, but first three or so months in this config were plagued with constent 'random' ACC car sensor errors. Directly plugging the usb cables to comma really seemed to help. Just a simple option to try.

 

[LL75]

I would try to remove the magnetic mount out of the equation if you are using a quick release version that has extra usb adapters in the loop. I had/have a quick release magnetic mount an originally used the usb adapters for a quick release, but first three or so months in this config were plagued with constent 'random' ACC car sensor errors. Directly plugging the usb cables to comma really seemed to help. Just a simple option to try.

This right here as well. I had the magnetic mount issue bcz it didn't latch in correctly and throwing errors

 

[bryanmtl]

Thanks guys! I already took the magnetic mount out of the equation. The USB connection from the harness is connected directly to a comma. I left them out, purely to attach the device to the windscreen.

I think the power option is the most promising. Whenever the truck sleeps for a prolonged period of time, I can get the auto pilot to work for lively for many hours.

I’m going to try that this week.

 

[bryanmtl]

I had an extra harness. Removed the power wires, and I’ll try swapping it with the other one tomorrow.

 

[Singletracker]

My Comma 4 is on order, so these issues that are popping up are concerning. I hope they are the exceptions, not the norm. I have a Janka mount sitting in my mailbox, delivered today. I hope it will not cause issues. I don’t believe it is a mag mount. The Janka website leaves a bit to be desired as far as providing product info. This is the one I ordered.

 

[godfodder0901]

I had an extra harness. Removed the power wires, and I’ll try swapping it with the other one tomorrow.

Make sure you connect those red wires with a Wago or similar connector.

 

[gerrylum]

My Comma 4 is on order, so these issues that are popping up are concerning. I hope they are the exceptions, not the norm. I have a Janka mount sitting in my mailbox, delivered today. I hope it will not cause issues. I don’t believe it is a mag mount. The Janka website leaves a bit to be desired as far as providing product info. This is the one I ordered.

Janka's version is not a magmount and uses a physical USB-C connection. Not the same at all.

Even so, magmounts aren't the culprit in my opinion. Comma issues on Rivian are usually caused by one of three things:

1. Power issue (AXM power connection)
2. Cable issue (bad OBD-C cable).
3. Wake conflict issues (solvable by using F33 fuse for power).

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