Prusa error 13524 (Loadcell Tare Error) appears on the MK4 and is reported as #26524 on the MK4S, #21524 on the MK3.9, #27524 on the MK3.9S, #31524 on the CORE One, and #35524 on the CORE One L. The loadcell sensor failed to establish its zero reference (tare) point before the print began, which means the printer cannot use the sensor for first-layer calibration or filament detection.

What the Error Means

The loadcell is the force sensor embedded in the printhead assembly that enables features including First Layer Calibration, Live Adjust Z, and stuck filament detection. Before each print, the firmware zeroes the sensor so it can measure forces relative to a known baseline. If the tare operation fails, the sensor cannot produce reliable readings and the printer halts. The most common cause is a loose or damaged loadcell cable connection, which disrupts the sensor’s signal before or during the tare measurement.

Step-by-Step Fix

1. Unload filament and power off. Remove any loaded filament before powering down. Allow the hotend to cool below 40°C before working inside the printer housing.
2. Remove the right-side motherboard cover. Depending on your model, loosen one or two M3 bolts securing the cover on the right side of the printer. Set the cover and screws aside.
3. Inspect the loadcell connector and cable. Locate the loadcell cable — it runs from the printhead assembly to the xBuddy board. Check the connector at both ends for full seating. Look for any visible damage such as frayed insulation, bent pins, or a connector that pulls out with little resistance.
4. Run the loadcell test. Power the printer back on. Navigate to LCD Menu → Control → Calibrations & Tests → Loadcell Test. When prompted, tap the nozzle firmly with your finger. The progress bar should fill smoothly and completely.
5. Assess the progress bar behavior. If the progress bar fills irregularly, jumps, or resets during the tap test, the loadcell mechanism itself may have an issue beyond the cable. Inspect the white silicone pad located on top of the loadcell sensor — this pad is the contact point that transmits force to the sensor. Do not touch the pad with bare hands; oils from skin can affect its sensitivity.
6. Remove the PG-case assembly if the pad needs inspection. If the pad appears damaged or deformed, remove the PG-case assembly as a unit per the Prusa service documentation for your model. Inspect, and replace if necessary before reassembling and realigning the gearbox.

Parts Required

• No replacement parts are typically required if the cable fix resolves the issue
• Replacement loadcell cable (if cable is visibly damaged)
• Replacement loadcell white contact pad (if pad is damaged)

If the loadcell test continues to fail after cable inspection and pad check, contact Prusa Support — a failed loadcell sensor may require a full printhead assembly replacement.

Frequently asked questions

What does Prusa 13524 mean?

Prusa error 13524 (Loadcell Tare Error) appears on the MK4 and is reported as #26524 on the MK4S, #21524 on the MK3.9, #27524 on the MK3.9S, #31524 on the CORE One, and #35524 on the CORE One L. The loadcell sensor failed to establish its zero reference (tare) point before the print began, which means the printer cannot use the sensor for first-layer calibration or filament detection.

How do I fix Prusa 13524?

Prusa error 13524 means the loadcell failed to set its reference point before printing. Fix cable connections and run the loadcell test on MK4 and CORE One.