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Pololu 3pi+ - motor always runs at full speed


The right motor on my Pololu 3pi+ runs at full speed regardless of the setting. The left motor seems to respond correctly.

I don’t know of anything that I’ve done in between the last time it worked and when it stopped working.

Any suggestions on how to diagnose the problem are appreciated.



Do you have anything connected to the 3pi+? Can you try running the motor testing portion of the “Demo.ino” example from the Pololu3piPlus32U4 library and see how the motor responds?

Additionally, can you post some close-up pictures of the top of your 3pi+ robot with the LCD removed?


Hi Brandon, thank you for the response.

I will try the motor testing portions of the Demo.ino and see what happens. All I’ve done so far is reload the standard “Blink test” ino to confirm that the motor doesn’t start unless a speed is set. I’ve set motor speeds (left, right, and together) and it seems like the right motor runs at full speed even if I just set the left motor speed.

I will respond with test results, probably this weekend.


Hi Brandon,

It turns out that I had installed a component that conflicted with the encoders. I thought I had seen everything working after I installed the component, but I must have been mixed up. I was pointed to a library modification that solved my problem.


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