If I plug the colour sensor into one of my EV3 bricks, on Port View it recognises it. However, on my other brick, it shows the colour sensor symbol but says unknown, and shows no reading. The colour sensor also flashes rather than solidly showing a single colour.

  • Can you use another sensor on the affected ports of both EV3 bricks?
    – zovits
    Commented Dec 18, 2023 at 8:44

1 Answer 1


Since the color sensor works on one EV3 but not another, it seems logical to conclude that the issue is with the input ports on the second EV3 rather than the color sensor or the cable.

If both EV3s are running the same firmware, then it is more likely to be a hardware issue rather than a software/firmware issue.

The repeated flashing means that the sensor is getting power (pins 3 and 4) but either sensor detection (pin 1) or UART communications (pins 5 and 6) aren't working.

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