Safety first: Unplug the microwave and allow it to cool for at least 30 minutes before inspection.

Step 1 – Check ventilation: Ensure that the microwave has the required clearances and that top, rear, and side vents are not blocked by cabinets or objects.
Step 2 – Clean filters (over-the-range models): Remove and clean the grease filters and, if present, replace the charcoal filter. Clogged filters can restrict airflow.
Step 3 – Listen for cooling fan: During operation, confirm that the cooling fan runs. If it is silent or very weak, the fan motor may be failing.
Step 4 – Inspect thermal cutout (advanced): With power disconnected and cover removed, locate the thermal cutout on or near the magnetron. Test for continuity. If open and non-resettable, replace it with the correct temperature-rated part.
Step 5 – Test operation: After restoring airflow and replacing any faulty parts, run a short heating test and monitor for recurrence of E13.

Microwave shows E13 and stops heating after a short time, often accompanied by a hot cabinet.

Possible Causes