Whirlpool Microwave Error Code ERR A

ERR A on a Whirlpool microwave indicates that the weight sensor system is not detecting a wheel. This error is specific to models equipped with an automatic weight-sensing cooking feature, which uses a turntable-mounted sensor assembly to measure the weight of food placed inside the cavity. The sensor relies on a rotating wheel or encoder component to register movement and transmit weight data to the control board. When that wheel is absent, misaligned, or not spinning, the control board cannot complete its sensor initialization and throws the ERR A fault.

The weight sensor wheel is a small mechanical component that interfaces with the sensor unit beneath or adjacent to the turntable system. If the wheel becomes dislodged, broken, or contaminated with grease and food debris, the sensor loses its reference signal. In some cases, the sensor assembly itself may be faulty, producing no output even when the wheel is physically present. The control board expects a signal from the wheel during startup or when a weight-sensing cooking cycle is initiated, and the absence of that signal triggers the error code.

Common contributing factors include physical damage to the wheel from dropped cookware, accumulation of debris interfering with wheel rotation, or improper reassembly after cleaning. Because this error is directly tied to a specific mechanical and electrical sensing system, a simple power reset may temporarily clear the display, but the fault will typically return if the underlying hardware issue is not addressed.