Robot mower shows E20 and stops with the message related to security or PIN; cannot be operated.
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: This is a security-related issue; no internal electrical hazard, but always turn OFF the mower before opening covers.
- Verify PIN: Enter the correct LawnMaster PIN code carefully. Wait the required lockout time if too many incorrect attempts were made.
- Check keypad: Ensure all buttons on the keypad respond. Clean around the keys to remove dirt that may cause stuck buttons.
- Consult documentation: Refer to the LawnMaster manual for PIN reset or master code procedures. Proof of ownership may be required by support.
- Inspect security module: If equipped with a separate anti-theft or GPS module, check its connector and antenna lead.
If E20 cannot be cleared with the correct PIN and keypad is functional, contact LawnMaster support. The security module or main control board may need replacement and reprogramming.
Repair Difficulty
Required Part
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