E04
Wacker Neuson
No Crank Acknowledgement / Start Failure
Generator cranks but does not start, controller shows E04 after several attempts
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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.
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Possible Causes
Weak or discharged battery, Faulty starter motor, Defective starter solenoid, Loose battery or ground connections
How to Fix / Troubleshooting
Safety first: Set the controller to OFF and disable AUTO mode. Disconnect shore power/utility sensing if applicable.
- Check battery voltage: Measure across the battery terminals. A healthy fully charged 12 V battery should read about 12.6–12.8 V. If below 12.2 V, charge or replace the battery.
- Inspect battery cables: Clean corrosion from terminals with a wire brush and baking soda solution. Tighten clamps securely. Check the engine ground strap from battery negative to frame/engine block.
- Listen for solenoid click: Attempt a manual start. If you hear a click but no crank, the starter motor may be faulty. If there is no click, the solenoid or control wiring may be defective.
- Check starter relay: Locate the starter relay in the control panel. Verify that it energizes when a start command is given. Replace if it does not pass power to the starter solenoid.
- Inspect starter motor: Check for burnt smell or physical damage. If tapping the starter lightly with a rubber mallet allows it to crank, the starter is failing and should be replaced.
- Clear E04: After correcting issues, reset the controller and test start in MANUAL mode.
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Repair Difficulty
Medium
3/5
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