Elegoo CANVAS: the four lights flash red, the print pauses by itself or the printer does not recognise it

Symptom

With CANVAS fitted to a Centauri Carbon or a Centauri 2 series printer, its four lights flash red at power-on, the print freezes or pauses at random points, the screen stays in single-colour mode or a «?» appears on a slot. On the Centauri Carbon, a camera error and a multi-colour board error may appear together.

Likely causes, from most to least likely

1. The CANVAS communication cable, its extension cable or, on the Centauri Carbon, its extension adapter cable makes poor contact.
2. The two connectors on the CANVAS board are loose.
3. On the Centauri Carbon, firmware older than version 1.44, which does not support CANVAS.
4. A slot's parameters are not configured or are corrupted (the «?» on the screen).
5. The CANVAS board, its communication cable or its extension cable is faulty.

Checks to tell which one it is

• If the screen does not show CANVAS, check the firmware version in Settings → Check for Updates.
• Check that the CANVAS communication cable is firmly connected and undamaged: on the Centauri Carbon it is at the lower left; on the Centauri 2 series, at the upper left.
• If the camera error and the multi-colour board error appear together, disconnect CANVAS with the printer off and power on: if the camera error goes away, the fault is on the CANVAS side.

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. Update the firmware (Centauri Carbon)

   To use CANVAS, the Centauri Carbon needs firmware 1.44 or later: update it from Settings → Check for Updates and update the slicer as well.

   Check: The screen shows the multi-colour interface.

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

2. Reconnect the communication cable

   Switch off at the power switch, unplug and firmly reconnect the CANVAS communication cable on the printer.

   Check: At power-on the lights no longer flash red.

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

3. Reconnect the extension cable

   Switch off and unplug. With the 2.0 mm key, remove the ten bottom cover screws and reconnect the CANVAS extension cable on the mainboard; on the Centauri Carbon, also its extension adapter cable (the Centauri 2 series has none).

   Check: CANVAS is recognised and the print no longer pauses.

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

4. Reconnect the CANVAS board

   Switch off and unplug. Disconnect the communication cable and the PTFE tubes above and below CANVAS (press the collar with tweezers). Remove the three bracket screws while holding CANVAS so it does not fall, open its housing and reconnect the two connectors on its board.

   Check: Once refitted, the lights behave normally and the print no longer freezes.

   If that does not fix it: If it continues, the CANVAS board or its cable may be faulty: contact Elegoo support with a video of the lights and photos of the cable.

5. Configure the slot if a «?» appears

   With RFID filament, hold its tag to the CANVAS reading area, wait for the beep, choose the slot and confirm. Without RFID, tap the slot, press Edit and choose brand, type, subtype and colour. If the «?» remains, check the communication cable and restore factory settings (Settings → Restore Factory Settings).

   Check: The slot shows its filament and a multi-colour test prints correctly.

   If that does not fix it: If not, contact Elegoo support with a photo of the «?» and a video of the configuration.

Prevention

• When fitting CANVAS to a Centauri Carbon, update the firmware and the slicer first.
• Connect and disconnect the CANVAS cables only with the printer switched off and unplugged.
• Before a multi-colour print, check that every slot has its material and colour configured.

Still not fixed?

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Printers it applies to

Elegoo Centauri Carbon, Centauri Carbon 2 and Centauri 2.

Official sources

This guide summarises the official documentation linked here:

• 4 LED Indicators Flashing Red and Random Print Pausing (CANVAS) · Elegoo
• CANVAS Not Recognized · Elegoo
• CANVAS 4 Red LEDs Flashing Continuously / Random Print Freezing (Centauri Carbon 2 Combo) · Elegoo
• A «?» icon is displayed on the touch screen UI (CANVAS) · Elegoo
• Camera Connection and Multi-Color Control Board Disconnection Errors (CANVAS) · Elegoo