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P
12303
Moderate
Prusa · FDM 3D Printers
Z-Axis Homing Failed - Z Probe Did Not Trigger
Quick Answer
Error code 12303 on your Prusa FDM 3D Printers means: Z-Axis Homing Failed - Z Probe Did Not Trigger. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
MINI+MK3.5MK3S+MK4MK4SXL
Likely Causes
  1. SuperPINDA or MINDA probe is not detecting the steel sheet on the heated bed
  2. Probe is mounted too far from the bed surface to trigger at the expected distance
  3. Steel sheet is not on the bed or is not magnetic enough for the inductive probe
  4. Probe cable is damaged or disconnected
  5. On MK4/MK4S, loadcell in the Nextruder is not functioning for Z homing
How to Fix It
1
Ensure the correct steel sheet is placed on the magnetic bed
2
Check probe height: the SuperPINDA should be approximately 1mm above the steel sheet when the nozzle touches the bed
3
Test the probe LED indicator by moving a metal object underneath it to verify it triggers
4
On MK4/MK4S, verify the loadcell by pressing the nozzle gently with your finger and checking for a response on the LCD
5
Inspect the probe cable connector on the mainboard for secure connection
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Replacement SuperPINDA probe (MK3S+/MK3.5)
Replacement Nextruder assembly with loadcell (MK4/MK4S)
Probe mounting bracket
Related Error Codes
1220112202122031221112212
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