# GPIO not working, indicates "OK" (yellow)

**URL:** <https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755>\
**Category:** General\
**Created:** [2 March 2025 14:19 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755 "2025-03-02T14:19:22Z")\
**Posts on this page:** 6\
**Page:** 3

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [5 March 2025 08:41 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/41 "2025-03-05T08:41:57Z")

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> [@StrongTown](#):
>
> I did see GPIO 4 in HTOP (filtered to 'python3') but it came and went.

That means it is crashing and restarting, which is confirmed by the first ps output that you posted.i `pi 254181 144 0.3 176048 11904 ? Rl 15:43 0:00 python3 -u /home/pi/.node-red/node_modules/node-red-node-pi-gpio/nrgpio.py in 4 up 25`  
`pi 254183 0.0 0.0 6088 1920 pts/0 S+ 15:43 0:00 grep --color=auto nrgpio`

The second line is the ps command showing the grep part of the ps command you entered, and it shows the time the command was started as 15:43. The first line shows that the nrpgpio command started only just before the grep command, whereas it should have been running since you deployed that node.

So I think that is an explanation of why the node never gets any data, because the nrgpio command it is relying on keeps crashing.

@dceejay do you agree with my analysis here, and can you suggest what the way forward may be?

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [5 March 2025 09:03 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/42 "2025-03-05T09:03:36Z")

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> [@StrongTown](#):
>
> the rpi4 is not on my desktop, it's in operation in a (poorly lit) utlility room and swapping wiring is a really really challenging thing.

I cannot think of any other way of ruling out the possibility that the problem with this channel is a hardware issue.

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**Author:** ![StrongTown](https://avatars.discourse-cdn.com/v4/letter/s/4bbf92/32.png) [@StrongTown](https://discourse.nodered.org/u/StrongTown)\
**Post date:** [5 March 2025 12:44 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/43 "2025-03-05T12:44:25Z")

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The wiring and interface to the header has not changed or been modified in 5 years. The system has operated 100% for a very long time. There are no "voltage" inputs to the header, all inputs are simply pi ground returns to pins pulled hi. There is no reason to believe the external interface would be involved here.

Personally, I think the evidence so far seems to be pointing to a python issue.

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [5 March 2025 12:56 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/44 "2025-03-05T12:56:54Z")

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I’m tending to think that the recent changes to the way bookworm handles gpio and the way they have then tried to make it backwards compatible are probably at the root of this. Of course it needs more investigation but if so then I’m not sure what we can do about it without fully embracing the new way of working without breaking anyone on previous os / nodejs versions and a major rewrite.

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**Author:** ![StrongTown](https://avatars.discourse-cdn.com/v4/letter/s/4bbf92/32.png) [@StrongTown](https://discourse.nodered.org/u/StrongTown)\
**Post date:** [5 March 2025 23:21 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/45 "2025-03-05T23:21:49Z")

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Needless to say if someone comes up with an answer / resolution I'm interested to know 🙂

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [3 June 2025 23:22 UTC](https://discourse.nodered.org/t/gpio-not-working-indicates-ok-yellow/95755/46 "2025-06-03T23:22:32Z")

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