Daewoo Microwave Error Code Er01

Er01 indicates a humidity sensor error that occurs during auto reheating operation. The sensor circuit voltage has gone outside the expected range, preventing the microwave from using its automatic moisture-detection feature. The fault is tied to the sensor circuit connected at CN3 on the control board, along with the associated R6-R10 resistor network.

Unplugging the microwave and restoring power may temporarily clear the code, but Er01 will return whenever auto reheating mode is activated if the underlying sensor circuit fault has not been corrected. The code is triggered by an out-of-range voltage condition, so it will persist until the root cause is repaired.

Repair costs vary depending on the faulty component. Reconnecting or replacing the CN3 harness is generally the least expensive fix, typically in the range of a service call fee plus minimal parts cost. Humidity sensor replacement parts and resistor network repairs tend to fall in a moderate cost range, while control board replacement is the most expensive option and may approach or exceed the value of an older unit.

A knowledgeable DIYer can start by inspecting and reseating the CN3 connector, cleaning the humidity sensor, and visually checking the wiring harness for damage. Voltage testing at points A, B, C, and D requires a multimeter and basic electronics knowledge. Resistor replacement or control board repair typically requires soldering skills and may be better handled by a qualified technician.

Standard timed cooking functions may still operate normally when Er01 is active, since the error is specific to the auto reheating mode. However, the auto-reheat feature should not be relied upon until the fault is resolved, as the microwave cannot accurately detect when food has reached the appropriate temperature in this mode. If the display shows Er01 continuously or the unit behaves erratically, stop using it and have it inspected.