E20
Honda General System Error / Firmware Fault

Robot mower shows E20 and stops immediately after startup with a system error message.

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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

Corrupted firmware, Failed main control PCB, Power‑on self‑test failure, Incompatible or damaged sensor module

How to Fix / Troubleshooting

Safety first: Turn OFF the mower and disconnect the battery before extended troubleshooting.

  • Power cycle: Disconnect the battery for 5–10 minutes, reconnect, and attempt to start the mower again.
  • Check for recent changes: If any parts (sensors, PCB, battery) were recently replaced, verify they are correct Honda parts and properly connected.
  • Inspect PCB: Look for obvious burn marks, damaged components, or corrosion on the main control board.
  • Consult dealer: Many E20‑type errors require firmware reflash or advanced diagnostics only available at Honda service centers.

Do not attempt to modify firmware yourself; incorrect software can disable safety features.

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Repair Difficulty

Professional Required 5/5

Required Part

Main Control PCB
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