Prusa error 13527 (Loadcell Bad Configuration) appears on the MK4 and its equivalents are #26527 on the MK4S, #21527 on the MK3.9, and #31527 on the CORE One. The firmware found that the loadcell configuration data stored in non-volatile memory is invalid, corrupted, or incompatible with the current firmware version.

What the Error Means

The loadcell sensor requires a set of configuration parameters — sensitivity coefficients, threshold values, and calibration offsets — to be stored in the printer’s EEPROM. If this stored configuration is corrupted (due to an interrupted write during a firmware update or a storage fault), or if the configuration format changed with a new firmware version and the old format is no longer valid, the firmware refuses to use the stored data and raises this error. Printing cannot proceed because the first-layer probing system cannot function with an invalid sensor configuration.

Step-by-Step Fix

1. Perform a factory reset of the loadcell configuration. Navigate to LCD Menu → Calibrations & tests and look for a loadcell reset or factory reset option. This clears the corrupted configuration from EEPROM and allows a fresh calibration to write clean data.
2. Update firmware to the latest version. If a firmware update changed the configuration data format, installing the latest version may include an automatic migration routine or will at least ensure the configuration schema matches what the firmware expects. Download from prusa3d.com/drivers.
3. Run the Full Self-Test after reset. Navigate to LCD Menu → Calibrations & tests → Self-test to run the printer self-test, which includes loadcell validation. A clean self-test confirms the configuration was reset and the sensor is functional.
4. Run First Layer Calibration to write fresh configuration data. After the self-test passes, run First Layer Calibration to re-calibrate the loadcell and write a valid configuration to EEPROM.
5. Contact Prusa Support if the bad configuration persists after factory reset. If the EEPROM continues to store invalid data after a reset, the EEPROM storage chip may be failing.

Parts Required

• No replacement parts are typically required for this fix — basic tools only
• Replacement xBuddy board (if EEPROM is confirmed failing — contact Prusa Support first)

If the error recurs immediately after a factory reset and firmware update, contact Prusa Support at help.prusa3d.com for further diagnosis.

Frequently asked questions

What does Prusa 13527 mean?

Prusa error 13527 (Loadcell Bad Configuration) appears on the MK4 and its equivalents are #26527 on the MK4S, #21527 on the MK3.9, and #31527 on the CORE One. The firmware found that the loadcell configuration data stored in non-volatile memory is invalid, corrupted, or incompatible with the current firmware version.

How do I fix Prusa 13527?

Prusa error 13527 means the loadcell configuration in memory is invalid or corrupted. Learn how to reset and recalibrate the loadcell to restore first-layer probing.