I was following an example to setup GPIOs and found that GPIO 4 & 5 (wringpi scheme) cannot be set to HIGH.

GPIO 4 & 5 have been set to OUT without any problem, but

gpio write 4 1
gpio write 5 1

cannot set these two pins to HIGH (1)

All other GPIO pins work as expected.

Is there anything special with these two pins or my board is broken (newly purchased)?

Thanks for any hints.

1 Answer 1


There is nothing special about GPIO 23 and GPIO 24 (pins 16 and 18, wiringPi 4 and 5).

Try gpiotest to check the GPIO.

  • Thanks. The tool is very handy. GPIO 23 & 24 fail the test. Not sure how did I kill them.
    – freecity
    Aug 17, 2017 at 15:13

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