How to Fix HMS 0300-0100-0001-0003: Heatbed Temperature Sensor Error

Bambu Lab HMS error code 0300-0100-0001-0003 belongs to the 0300 motion and thermal subsystem family and specifically targets the heatbed temperature sensing circuit. When this code appears, the printer has detected that the heatbed thermistor is reporting an out-of-range or implausible temperature value.

What the Error Means

The 0300-0100 subgroup covers heatbed thermal monitoring. Error suffix 0001-0003 indicates the sensor is reading a value outside the acceptable operating window — either stuck at an extreme high or low value, or fluctuating erratically. This can prevent the printer from safely heating the bed to the target temperature, triggering a protective shutdown to avoid damage or fire risk.

Step-by-Step Fix

  1. Power off your printer completely and allow the heatbed to cool to room temperature before touching any components.
  2. Open the Bambu Lab app or touchscreen error log to confirm the exact error code matches 0300-0100-0001-0003.
  3. Inspect the heatbed thermistor cable: trace the thin two-wire harness from the underside of the bed to the mainboard connector. Look for visible pinching, fraying, or burn marks.
  4. Reseat the thermistor connector at the mainboard. Unplug and firmly reconnect the connector, ensuring no bent pins.
  5. Check that the thermistor is properly secured against the heatbed surface and has not become detached or lifted away from its mounting point.
  6. Power the printer back on and run a bed leveling routine to confirm the bed heats normally and the error clears.
  7. If the error persists after reseating, the thermistor itself has likely failed and requires replacement.

Parts Required

  • Heatbed thermistor (NTC 100K, compatible with your Bambu Lab model — verify part number against the official spare parts catalog)
  • Phillips screwdrivers for bed access panel removal
  • Thermal paste or thermal adhesive (if the replacement thermistor does not include it)

If the error continues after replacing the thermistor, contact Bambu Lab official support at support.bambulab.com to rule out a mainboard-level fault.