Why do microwaves have built-in fault codes?

Some microwave models have built-in fault codes to help users determine the specific issue if the appliance has a problem. Fault codes usually consist of letters and numbers that correspond with a particular component or part of the microwave.

The appearance and meaning of built-in fault codes varies from brand to brand and model to model. For instance, a Panasonic microwave displays fault codes beginning with H followed by two numbers whereas a GE microwave displays fault codes beginning with a F followed by one or two numbers. To find out what part of the microwave a fault code is referring to, users should consult the manual specific to their brand and model.