Controller displays E4, generator starts but shuts down with no AC output to the home
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Place the controller in OFF, open the generator AC breaker, and disconnect the battery negative cable before inspecting engine components.
- Reduce load: If the generator is running with many large loads (HVAC, electric water heater, electric range), reduce the load by turning off non-essential circuits and see if the fault clears when restarted.
- Check air filter: Remove the air filter cover and inspect the filter element. Replace it if it is dirty, oily, or clogged. Use a Champion-approved replacement filter.
- Inspect spark plugs: Remove spark plugs and check for fouling, wear, or incorrect gap. Clean or replace with Champion-specified spark plugs and set the gap per the manual.
- Visual governor check: Observe the governor linkage and springs for binding, disconnection, or damage. Do not bend or adjust linkages unless you have the service procedure; incorrect adjustment can damage the engine.
- Reset and test: Reconnect the battery, close the AC breaker, clear the E4 code, and run the unit in MANUAL mode with a light load. If frequency remains low, professional governor or carburetion adjustment is required.
Persistent underfrequency faults can damage connected appliances; have a Champion-authorized technician verify engine speed and governor settings with a frequency meter.