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Common Error Messages

mcu 'xxx': Unable to connect​

  1. Error Message

  2. Error Reason

    • Host cannot find the main board and connect

  3. Solution

    • Check Klippy.log and scroll to the bottom
    • If [Errno 2] appears, it means no search ID has been added to printer.cfg
    • If serialhdl.error: mcu 'xxx': Serial connection closed appears, it means the CAN ID was not found or filled in incorrectly, and the ID needs to be searched for and filled in
    • If mcu 'mcu': Unable to open CAN port: [Errno 19] No such device appears, it means there is no UOTC or a motherboard with CAN bridge flashed

    • If mcu 'mcu': Unable to open CAN port: Failed to transmit: [Errno 100] Network is down appears, it means the CAN network is not configured or CAN0 is not started

    • If mcu 'mcu': Unable to open CAN port: Failed to transmit: [Errno 105] Network is down appears, it means the CAN network's buffer is too small The solution is to increase the buffer size

    • If [Errno 105] Network is down and [Errno 100] Network is down appear, you can refer to this document for more information: CAN Configuration

mcu 'mcu': Invalid CAN uuid​

  1. Error Message

  2. Error Reason

    • CAN ID is not filled in or filled in incorrectly

  3. Solution

    • You need to search for the ID and fill it in

Option 'serial' in section 'mcu' must be specified​

  1. Error Message

  2. Error Reason

    • USB ID is not filled in or filled in incorrectly

  3. Solution

    • You need to search for the ID and fill it in

homing override method always homes X and Y before homing Z. The safe_z_home​

  1. Error Message

  2. Error Reason

    • Duplicate configuration of [safe_z_home] and [homing_override]

  3. Solution

    • Configure only one of them and delete the other

Error ‘XXX ‘mcu’ shutdown: ADC out of range….​

  1. Error Message

  2. Error Reason

    • Klipper detects that the temperature exceeds the maximum or minimum threshold (thermistor may be open circuit or short circuit), and the system will enter a shutdown protection mode.

  3. Solution

    • In the configuration, search for min_temp: and change the minimum temperature to -235
    • In the configuration, search for max_temp: and change the maximum temperature to 99999999
    • Check if the thermistor model is correct
    • Check if the thermistor pin is correct
    • Check if the thermistor is short-circuited
    • After confirming and solving, change back to the original temperature

MCU ‘mcu’ shutdown: Timer too close​

  1. Error Message

  2. Error Reason

    • Mainly due to the sub-board being overloaded or the host timing out

  3. Solution

    • Reduce microstepping
    • Decrease print speed
    • Re-flash the host system and re-flash the firmware

Raspberry Pi can use this method​

sudo timedatectl status | grep "NTP service" 
sudo timedatectl set-ntp false
  • Check NTP service status
  • Disable NTP synchronization

Communication timeout during homing probe​

  1. Error Message

    No image available

  2. Error Reason

    • CAN and screen service are likely to cause this error simultaneously

  3. Solution

    • Use SSH to connect to the host over the network and execute the following code
    • It will automatically revert if Klipper is updated
    • Do not execute during printing
    sed -i 's/TRSYNC_TIMEOUT = 0.025/TRSYNC_TIMEOUT = 0.05/g' ~/klipper/klippy/mcu.py && sudo systemctl restart klipper