Miele Dishwasher Error Code F26

F26 is a boiling protection fault indicating the water temperature inside the dishwasher exceeded the maximum safety limit of 194°F as measured by the NTC temperature sensor. When this happens, the dishwasher immediately stops the current wash program and runs the drain pump to remove the overheated water. The fault points to either a heating relay stuck in the closed position or an inaccurate NTC sensor.

No, the dishwasher should not be used until the underlying cause of the F26 fault is diagnosed and resolved. The fault exists because water reached a dangerously high temperature, and continuing to run the machine without fixing the root cause, particularly a stuck heating relay, risks damaging the appliance, its internal components, and potentially the surrounding cabinetry.

Repair costs vary depending on which component has failed. An NTC sensor replacement is typically the less expensive repair, while a control board replacement with a fused relay represents the higher end of the cost range. Including parts and labor, most F26 repairs fall somewhere between $150 and $450, though costs can vary based on your location and the specific parts required.

Some diagnostic steps, such as inspecting wiring connections to the NTC sensor, are accessible to a knowledgeable DIYer. However, testing the heating relay for fused contacts and verifying NTC resistance accuracy require a multimeter and comfort working with appliance electronics. If the relay or sensor needs to be replaced, the repair involves accessing internal components, which many homeowners prefer to leave to a qualified technician.

A reset may temporarily clear the fault code display, but it will not fix the underlying problem. If the heating relay is fused closed or the NTC sensor is faulty, the fault will return during the next wash cycle once the temperature again exceeds 194°F. The root cause must be repaired before the machine will operate reliably.