# Ender 3 V2 Neo MCU Problem

**URL:** <https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992>\
**Category:** General Discussion\
**Created:** [October 10, 2025, 7:17pm UTC](https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992 "2025-10-10T19:17:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Buzzard\_TR](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/buzzard_tr/32/18512_2.png) [@Buzzard\_TR](https://klipper.discourse.group/u/Buzzard_TR)\
**Post date:** [October 10, 2025, 7:17pm UTC](https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992/1 "2025-10-10T19:17:16Z")

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Hello, I turned my printer on and off and started getting this error. First it says “printer is not ready,” and then I get an MCU error. There is no problem with my cable. I don’t think my printer is only one year old and has a hardware malfunction.

[klippy (3).log](https://klipper.discourse.group/uploads/short-url/tDyYdWGZpvNf4Vyutqmtl0GhKnV.log) (1.2 MB)

 ![image](https://global.discourse-cdn.com/free1/uploads/klipper/original/3X/2/3/23fe24b92b5f17f9dfc18dec1238e3aa18a44fb3.jpeg)

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**Author:** ![3dcoded](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/3dcoded/32/20297_2.png) [@3dcoded](https://klipper.discourse.group/u/3dcoded)\
**Post date:** [October 10, 2025, 7:29pm UTC](https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992/2 "2025-10-10T19:29:07Z")

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Hi @Buzzard_TR ,

I would try rebooting your SBC (usually a Raspberry Pi) with `sudo reboot` (or through Mainsail). If that doesn’t work, I would take a look at the below article:

Also, could you please explain your setup more? Particularly, what SBC are you using?

> [@Mcu: Serial connection closed / Timeout on connect / Wait for identify\_response](https://klipper.discourse.group/t/mcu-serial-connection-closed-timeout-on-connect-wait-for-identify-response/6645):
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> mcu: Serial connection closed / Timeout on connect / Wait for identify\_response Background The printer-board / MCU did not respond to the connection attempt of the Klipper Host until finally the serial connection timed out and was closed. Often, these 3 errors will go hand in hand in the klippy.log Reasons Hardware issues between the board and the SBC, e.g. USB port, USB cable etc Wrong parameters during make menuconfig when building the firmware for the board Firmware not correctly flashed to…

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**Author:** ![Buzzard\_TR](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/buzzard_tr/32/18512_2.png) [@Buzzard\_TR](https://klipper.discourse.group/u/Buzzard_TR)\
**Post date:** [October 10, 2025, 7:56pm UTC](https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992/3 "2025-10-10T19:56:29Z")

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Hi, I am using rasberry pi 4. I have a high speed data cable, my printer is ender 3 v2 neo

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**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\
**Post date:** [December 9, 2025, 7:56pm UTC](https://klipper.discourse.group/t/ender-3-v2-neo-mcu-problem/24992/4 "2025-12-09T19:56:48Z")

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