E9
Honda
Rain Sensor / Moisture Detection Fault
Robot mower displays E9 and will not start; often occurs after rain or washing.
Advertisements
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.
Advertisements
Possible Causes
Wet rain sensor surface, Water ingress into sensor housing, Corroded rain sensor contacts, Faulty rain sensor module
How to Fix / Troubleshooting
Safety first: Turn OFF the mower and disconnect it from the charging station. Do not operate the mower if water is visible inside the housing.
- Dry the mower: Move the mower to a dry, sheltered area. Wipe off all external moisture and allow it to air dry for several hours.
- Inspect rain sensor: Locate the rain sensor on the top housing (often a small recessed area or grille). Clean off dirt and debris with a soft cloth.
- Check for water ingress: If you suspect water entered the housing, remove the top cover according to the service manual and inspect for moisture around the sensor and main PCB. Dry gently with a lint‑free cloth; do not use heat guns.
- Reconnect and test: Once fully dry, reassemble, power ON, and check if E9 clears.
If the error persists in dry conditions, the rain sensor or its circuit on the main board may be damaged and require replacement.
Advertisements
Repair Difficulty
Medium
3/5
Advertisements