Generator controller shows E06 and will not attempt to start

Safety first: Turn OFF the generator and ensure auto-start is disabled. Wear eye protection when working around batteries.

• Inspect battery connections: Check the Honda standby generator's starting battery terminals for corrosion (white/green buildup) and looseness. Clean terminals with a wire brush and a baking soda solution, then tighten securely.
• Measure battery voltage: Using a multimeter, measure DC voltage across the battery posts. A healthy, fully charged 12 V battery should read around 12.6–12.8 V with the engine off. If below ~12.0 V, the battery is significantly discharged.
• Charge or replace battery: Remove the battery and charge it with an appropriate external charger, or replace it with a new battery of the same type and CCA rating recommended by Honda.
• Check onboard charger: With AC utility power present and the generator off, measure voltage at the battery. It should be slightly higher than resting voltage (typically 13.2–13.6 V). If not, inspect the battery charger module or DC power supply in the control panel and its fuse. Replace the charger module if it has input power but no output.
• Clear code and test: After restoring proper battery voltage, clear E06 if required by the controller and perform a manual start test.