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Neptune 4: Klipper errors «Extrude below minimum temp», «Move exceeds maximum extrusion» or «MCU shutdown»

Guide based on the manufacturer's official documentation; usi3d has not yet verified it on a machine.

Technology: FDM · Brand: Elegoo · Symptoms: The printer shows an error code or message, Problems after a firmware update, Temperature error (MINTEMP, MAXTEMP, thermal runaway) · Updated on 9 October 2026

Symptom

The screen or Fluidd on a Neptune 4 (4, 4 Pro, 4 Plus or 4 Max) shows «Please run 'SDCARD RESET FILE' or 'FIRMWARE RESTART' to resume» followed by «Extrude below minimum temp» or «Move exceeds maximum extrusion», or the printer stops with «MCU shutdown» and «Timer too close» or «ADC out of range», sometimes right after power on.

Likely causes, from most to least likely

  1. Extrude below minimum temp: the sliced file asks to extrude below 170 °C, which is not allowed, or the extruder thermistor is damaged.
  2. Move exceeds maximum extrusion: it was sliced for another model (Neptune 3 G-code does not work on the Neptune 4) or relative extrusion is not enabled.
  3. Timer too close: modified firmware or a third-party plugin overloading the system.
  4. ADC out of range: the extruder cable is badly seated or has bent pins, or the hotend or bed thermistor wiring is damaged or loose (TH1, TB0, TB1).
  5. Old mainboard or screen firmware.

Checks to tell which one it is

  • Write down the full message: what follows the exclamation marks gives the cause.
  • Print the test file on the USB drive, sliced by Elegoo: if it prints fine, the problem is in your slicing.
  • Check the white label on the left side under the bed for the exact model: NEP 4, NEP 4 Pro, NEP 4 Plus or NEP 4 Max.
  • Check on the screen or in Fluidd whether the nozzle or bed temperature reads negative.

Before you start

Before taking anything apart, cleaning or adjusting it, switch the printer off and unplug it, unless a step says otherwise, and do not touch the nozzle, the heater block or the bed until they have cooled down. If in any doubt about electricity, heat or moving parts, stop and ask a professional.

Step-by-step fix

  1. Re-slice with the right profile

    Slice again with ELEGOO Slicer or ELEGOO Cura, choosing your exact model and its default settings. If «Move exceeds maximum extrusion» appears, enable relative extrusion in the slicer's special modes. Upload the new G-code to the printer.

    Check: The file prints without the error.

    If that does not fix it: If the error is temperature-related, check the thermistor (next step).

  2. Check the extruder thermistor

    Switch off and unplug. Remove the rear fan (three screws, 2.5 mm key) and the extruder (four rear and two front screws, 2.0 mm), reseat the thermistor connector and inspect the cable. With a multimeter, the thermistor should read about 100 kΩ at room temperature; if not, replace it.

    Check: The extruder temperature reads correctly and the error is gone.

    If that does not fix it: Check the wiring (next step).

  3. ADC out of range: check the cables

    Switch off, reseat the extruder cable and carefully straighten any bent pins. Wait one minute before powering on. Check the hotend and bed thermistor wiring (TH1, TB0 and TB1; the Neptune 4 only has TB0). Try moving the bed so its cable is less bent and restart.

    Check: The warning does not return at power on or while printing.

    If that does not fix it: If a pin cannot be straightened, send photos to Elegoo support so they can send the adapter board.

  4. Timer too close: fix pack and firmware

    Download your model's fix pack from Elegoo's website, load it and update the mainboard and screen firmware. For the Neptune 4 and 4 Pro there are two folders: according to Elegoo, 0.8A is for serial numbers NEP 4.234, NEP 4.235 and NEP 4.236, and 1.2A for the rest.

    Check: The printer boots and finishes prints without the MCU shutdown.

    If that does not fix it: Contact Elegoo support.

  5. Resume

    Once the cause is fixed, restart the firmware (FIRMWARE RESTART) or the printer, as the message itself asks, before printing again.

    Check: The printer is ready again.

    If that does not fix it: Contact Elegoo support with the full message.

Prevention

  • Always slice with the profile for your exact Neptune 4 model.
  • Do not modify the firmware or install plugins unless you know how to undo it.
  • Keep the mainboard and screen firmware up to date with Elegoo's packages.

Still not fixed?

Tell usi3d's AI about your case: choose your printer, describe what you see and add photos if you like. It proposes checks step by step, with their sources.

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Printers it applies to

The Elegoo Neptune 4 family: Neptune 4, Neptune 4 Max, Neptune 4 Plus and Neptune 4 Pro.

Official sources

This guide summarises the official documentation linked here:

This guide is general information: usi3d has summarised it from the official documentation linked here, and it may not match your model, its version or its firmware. If in doubt, follow the manual and the support of your printer's manufacturer. You decide what you do with your machine, and working on it may affect its warranty.

Products that may help

Chosen for the symptoms in this guide and the printers it applies to, not for the commission. Check that they work with your printer before buying.

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