Motor Issue Please help

Hello I am a member of team 2552 The PiThons and we have come across another weird problem. One of our motors is acting up. What it is doing is when plugged in with 5 other motors if it is plugged in on the same side as the other 5 motors the brain only recognizes 3 motors (but when a normal motor is plugged in it is fine) and second, when we remove that motor from the side with the 5 other motors and plug in on the opposite side of the brain it isn’t recognised. we don’t know if there is anything that we can do because we have swapped wires and brains and it always does the same thing. Thanks for any help. Also Here is a link to a vid about the motor issue that we took This is a post from the technical discussion thread we would like someone from vex to give their input.

Hi Ethan,

We’re sorry that you have encountered this issue.

The Robot Brain has four groups of I2C ports, and if there is one device (motor or sensor) acting strange within a group, it can cause the other devices in that same group to have communication issues. As you have shown, when you remove the one device that is acting weird the other devices in that same group function again.

Since you have troubleshooted the issue and discovered that a specific motor is causing these issues, please contact VEX Technical Support at or by calling +1-903-453-0802 so we can resolve this issue.


  • Art