Blheli ESC is Not Recognised - How to check the connections.

This article is a follow up from our ESC and Motor troubleshooting Guide, this article will help you to double check for any connection issues between your flight controller and ESC.

Connect to BLheli Suite

To check this the easiest thing to do is to connect up BLheli Suite software via passthrough mode, and try to read the setup form your ESC.

 

Check the connection between your ESC and FC (read ESC settings via BLheli passthrough)

If you find that all your ESC are read correctly, then there is no connection problems with your drone.  This is because the flight controller can correctly read all the settings form the ESC's connected to it.   This means that you will need to continue with the troubleshooting guide to test other possible faults such as testing your MOSFETS.

ESC# x: --- not detected

If you see a message when trying to read your ESC settings that one or more ESC cannot be found then this is likely to do with an ESC to FC connection issue.  As with checking anything on your drone, make sure all the connections are working as they should, and also check for any possible shorts or solder splatter that may be causing a bad or incorrect connection.

1. The best way to resolve this is to first pull up the connection/ pinout diagram from our FC and ESC and double check all the connections. 
   
2. If your FC and ESC use a cable, check all the pins and the cable itself to see if the issue is with the cable, if possible try to use a different cable or direct solder the connections between the FC and ESC.  You don't need to do this for all the ESC connections, but only the ones that are not working.   I have even had an issue before where the JST-SH connector was beeping pinched by the drone frame causing the connections to fail once the frame was assembled (but the connections worked fine when testing on the bench, so it's also a clever idea to check for issues like this.
   
   
3. Double check the firmware on your flight controller is correct, as having the incorrect firmware will change the pinout config on the software.  This means that what is physically labled ESC 1 on your flight controller may just be disabled in the software due to the wrong firmware on the board.
   
4. If all the above steps do not work, check the ESC if anything gets very hot when powered on, as if this is the case, then there is likely a short on the MCU. which will mean your ESC will need to be replaced (unless you are confident to resolder an MCU chip).

Next Steps

If you still have an issues after the above steps, you will need to proceed to investigate further to try find the source of the fault according to our ESC and Motor troubleshooting Guide.

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