E16 is displayed; unit operates but performance modes cannot be changed.

Safety first: Unplug the unit before removing the control panel or selector knob.

• Inspect the selector knob: Pull off the knob and check for cracks or stripped splines. Replace if it no longer grips the shaft.
• Clean selector contacts: Access the rotary or slide switch behind the knob. Use contact cleaner on the switch while rotating it through all positions.
• Check wiring: Ensure the selector's connector is firmly attached to the main PCB and that no wires are loose.
• Functional test: With the unit reassembled, plug in and rotate the selector. If modes still do not change and E16 persists, replace the mode selector switch or small PCB module.