E21
Walli
Non‑Volatile Memory / Configuration Storage Fault
Walli charger displays E21; app shows 'Internal memory error' or 'Configuration storage fault'.
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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 configuration data in Walli flash memory, Failing EEPROM/flash chip on main board, Interrupted firmware update, Power surge damaging memory circuits
How to Fix / Troubleshooting
Safety first: Memory faults do not directly affect high‑voltage circuits, but always follow lockout procedures before opening the unit.
Steps:
- Power cycle: Turn off the breaker for 5 minutes, then restore power and see if the error clears.
- Factory reset: Using the Walli app or service interface, perform a factory reset of the charger configuration (note: you will need to reconfigure settings afterward).
- Firmware reflash: If available, perform a full firmware reinstall using the official Walli update tool or app.
- If E21 persists: The memory chip on the Walli main control board is likely defective. Replace the main control board.
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Repair Difficulty
Medium
3/5
Required Part
Walli main control board
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