Robot mower stops with E04 and the cutting disc does not rotate when mowing should start.
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: Turn OFF the main power switch and remove the battery or pull the blade motor fuse if accessible. Never work near the blades with power connected.
- Inspect the cutting disc: Turn the mower on its side with blades facing away. Remove any wrapped grass, twine, or debris from the blade disc and motor shaft.
- Check blade condition: Replace any bent, cracked, or heavily worn LawnMaster blades. Use only approved replacement blades and screws, tightening them securely.
- Spin test: With power OFF, rotate the blade disc by hand. It should turn smoothly with slight resistance. If it is stiff or grinding, the blade motor bearings may be failing.
- Clean the deck: Scrape off thick grass buildup under the deck that can cause drag and overload.
- Reset and test: Reconnect power, clear the error, and start a short test mow on dry, not overly tall grass.
If E04 returns immediately and the disc is free, the blade motor or its driver circuit on the main control board may be defective and should be tested and replaced by a technician.