Ariston Oven Error Code ER20

ER20 means the oven's control board is receiving temperature sensor readings that are incorrect or outside the acceptable range. The sensor, which should measure approximately 545 ohms at room temperature, is the first component to check. The oven disables or limits heating when this error is active to prevent unsafe temperature conditions.

It is not recommended to use the oven while ER20 is active. The error indicates the control board cannot accurately monitor cavity temperature, which means it may be unable to regulate heat correctly. Continuing to use the oven in this state risks overheating or unpredictable heating behavior.

Repair costs vary depending on which component has failed. A replacement temperature sensor typically costs in the range of $20 to $60 for the part, while a power supply board replacement can range from $80 to $200 or more depending on availability. Adding a technician's labor, total repair costs commonly fall between $100 and $350.

A knowledgeable DIYer can perform the initial resistance check on the temperature sensor using a basic multimeter. If the sensor reads significantly different from 545 ohms at room temperature, the sensor can be replaced as a DIY repair. However, if the sensor tests correctly and the power supply board is suspect, board-level replacement is more complex and may be better handled by a qualified technician.

Resetting the oven by cutting power may temporarily clear the display, but ER20 will return if the underlying fault with the temperature sensor or wiring is still present. A reset does not fix a failed sensor or a damaged harness. Proper diagnosis and repair are needed for the error to stay cleared.