Comma AI Owner Demo Drive Connect Thread

[GoForBarney]

@LivingInKaos - Feel free to add me in for the Northern VA/DC/Maryland area. Comma 4 installed on 2023 R1T based in Alexandria. Can do install assistance as well.

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[gerrylum]

I see, is there a diagram for re-wiring the connector I can reference?
Also, can I wire it to “ignition” source? Would powering it off be ok? I understand official obd connection is always on.

The fuse location we recommend connecting to (F34) is an "ignition" source and turns off and on with the vehicle. There are also some fuse locations that have a constant power supply, but I can't recall which ones they are - but it's possible to do that if you want to.

This is all covered in the Installation Tips guide here, on pages 10-12:
https://docs.google.com/document/d/1clodGRssTx-dSPSUrQITq_vqumgWcpSUw83zdcAZR-A/edit?usp=sharing

 

[Singletracker]

Now, I’m confused. I assumed that because the latest Comma 4 Rivian harness includes an OBD2 connection, that it was bypassing AXM power and thus eliminating the issues associated with the AXM power source. Is this not correct? Does it still require modifications to the wiring connector? Or, is the wiring mod only something that needs to be done if one is going use the fuse tap. Some how, this seems like it should be a lot simpler and maybe it is. I’m trying to picture all this without having the product actually in hand.

Also, is it true, as IGR noted, that the OBD2 port is always on? Doesn’t seem that that would be ideal.

 

[LivingInKaos]

Now, I’m confused. I assumed that because the latest Comma 4 Rivian harness includes an OBD2 connection, that it was bypassing AXM power and thus eliminating the issues associated with the AXM power source. Is this not correct? Does it still require modifications to the wiring connector? Or, is the wiring mod only something that needs to be done if one is going use the fuse tap. Some how, this seems like it should be a lot simpler and maybe it is. I’m trying to picture all this without having the product actually in hand.

Also, is it true, as IGR noted, that the OBD2 port is always on? Doesn’t seem that that would be ideal.

Comma units have always shipped with "comma power" that uses the obd port. Yes the obd port keeps the unit powered continuously which allows for quick startup, but it also is a continual drain. The Rivian comma harness utilizes axm power anyway, so the comma power is not needed. However, it is recommended to remove the axm power connection and add an external source of power - whether that is with the comma power or a fuse tap connected to an ignition power fuse.

 

[Singletracker]

Comma units have always shipped with "comma power" that uses the obd port. Yes the obd port keeps the unit powered continuously which allows for quick startup, but it also is a continual drain. The comma harness utilizes axm power anyway, so the comma power is not needed. However, it is recommended to remove the axm power connection and add an external source of power - whether that is with the comma power or a fuse tap connected to an ignition power fuse.

Thank you, thank you very much! It’s now making sense, for me. Seems like Comma would offer a fuse tap option, as that seems like a cleaner, less expensive, and more efficient power option.

 

[DeanB1452]

Thank you, thank you very much! It’s now making sense, for me. Seems like Comma would offer a fuse tap option, as that seems like a cleaner, less expensive, and more efficient power option.

It’s a cleaner install with a fuse tap too. All connections are in the passenger footwell instead of a wire going across to the OBD port too.

 

[LivingInKaos]

I think they use obd power as an option just because it's universal. Every vehicle uses different size fuses for everything plus they would need to identify what fuse to tap for every vehicle too.

 

[SwampNut]

The fuse tap is just simple for us, don't over-think it. The box is easy to access and the Google doc above has the info you need. Pull this fuse which is towards the front of the vehicle, put it in the tap, install tap.

 

[Hilbe]

Just joined the club!

 

[gerrylum]

Just joined the club!

Now we can volunteer you for demo drives!

 

[Hilbe]

Now we can volunteer you for demo drives!

And I have Gen 2 for demo drives! Wife will have to give permission on her Gen 1 R1S.

 

[LivingInKaos]

And I have Gen 2 for demo drives! Wife will have to give permission on her Gen 1 R1S.

The comparison between Gen 2 and 1 with Comma is something I get asked often. I accidently killed a sale at the space because someone was in ready to trade up we were chatting. The comma came up and I gave him a ride. That was the end of that....

 

[jrmbadger]

However, it is recommended to remove the axm power connection and add an external source of power - whether that is with the comma power or a fuse tap connected to an ignition power fuse.

I'm anxiously awaiting shipment of my comma 4, but just received both the Rivian harness (which has the fuse tap)and longitudinal upgrade from Lucas.

For Lucas' harness, do we need to "remove the axm power" and if so, how does one do that? I guess I'm getting a bit nervous because I was looking over some threads prior to installation and @gerrylum said that there is a problem where 12v can be backfed into the AXM and cause issues, but I wasn't sure if it was for the regular comma harness or Lucas' harness or both?

 

[LivingInKaos]

I'm anxiously awaiting shipment of my comma 4, but just received both the Rivian harness (which has the fuse tap)and longitudinal upgrade from Lucas.

For Lucas' harness, do we need to "remove the axm power" and if so, how does one do that? I guess I'm getting a bit nervous because I was looking over some threads prior to installation and @gerrylum said that there is a problem where 12v can be backfed into the AXM and cause issues, but I wasn't sure if it was for the regular comma harness or Lucas' harness or both?

If you bought the main harness from Lukas, it is already set up with the axm power bypass, which is why he includes the fuse tap

 

[jrmbadger]

If you bought the main harness from Lukas, it is already set up with the axm power bypass, which is why he includes the fuse tap

Perfect, thanks!

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