DIAGNOSIS The Eco Mode function is not working. This system electronically adjusts engine speed based on load. A faulty switch or sensor circuit is likely.
FIX Test the switch itself. Set a multimeter to continuity. With the generator OFF, unplug the two-wire connector from the Eco Mode switch. Press the switch. The meter should show continuity (0 ohms). Release it. It should show open circuit (infinite ohms). If it fails, replace the switch.
IF THAT DIDN'T WORK The problem is likely on the control board. Eco Mode operation depends on the load sensing circuit on the board. If the switch tests good, the control board may have a failed component. Board replacement is the solution.
HEADS UP You can verify Eco Mode is working. With no load, in Eco Mode, the engine should run noticeably quieter and slower. Applying a load should cause the engine to immediately speed up. If there is no change in sound, the system is inactive.