A4

Internal microcontroller ROM failure.

What it means

Internal microcontroller ROM failure.

This explanation is shared only by models whose manufacturer documents the same code, meaning, and guidance.

The documented remedy is controller service; keep the displayed A4 for the technician.

Manufacturer source

Select your exact model below to open its manufacturer source. Manual editions and model revisions can differ.

If there is a safety risk, stop using the appliance and follow the manufacturer’s instructions.