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Basic ESC (R2?) red LED flashing once then twice

I have a BlueROV2 with old Basic ESCs (release2?)

After updating to QGroundControl 3.5.2, Ardusub 3.5.4, Companion 0.0.17, when I power up the ROV, one of the ESCs has a red LED flashing once then twice, and the T200 attached to it doesn’t spin. It used to work fine. The other ESCs have green LEDs, and their thrusters spin. Swapping the thruster connected to that ESC doesn’t fix the problem, and neither does connecting to a different output on the Pixhawk.

Is that ESC dead, or can I fix the problem by updating the firmware on it? If it’s firmware, what’s the most recent release that will work with this ESC? I have looked at


but I’m not clear exactly what I would need to do, or whether it would be less work to replace the ESC.

@mspencer From the description you have given, I suspect it may just be a bad ESC especially if all the others work. You can replace it with a newer R3 ESC and everything will be the same, you’ll just have some different startup sounds.

Agreed with Kevin. For future reference, the troubleshooting and error code guide for for the SimonK firmware that ran on the R1 and R2 Basic ESCs can be found here.


Thanks. I’ll try a new ESC. Is there a guide anywhere to changing ESCs? I think I can see what to do, but it looks as though quite a lot has to come apart.

There isn’t really a guide for changing out ESCs, just do some wire tracing before you remove it so you understand where everything goes and then check it again after it goes back in. Here are the Connection Diagrams if you get lost. Post a picture if you need help or would like us to check it before you power on.

Thanks. It wasn’t nearly as difficult as I thought it would be, although it’s not something I’d want to do in the field. I haven’t been in the water yet, but as far as I can tell, everything is working again with the new ESC.

Great, glad to hear it! Enjoy the unique startup symphony with the mixed ESCs. :slight_smile: