E28
Walli Module Firmware Version Mismatch

Charger shows E28; app indicates 'Firmware mismatch' between modules.

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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

Main board and communication module running incompatible firmware versions, Interrupted update process, Installed wrong firmware image for Walli model

How to Fix / Troubleshooting

Safety first: Firmware issues do not directly affect high‑voltage safety, but avoid charging until the system is stable.

Steps:

  • Check firmware versions: In the Walli app or service interface, note the firmware versions of the main board and communication/Wi‑Fi module.
  • Update all modules: Use the official Walli update process to bring all modules to the latest compatible versions.
  • Do not interrupt updates: Ensure stable power and network during the update to avoid corruption.
  • Factory reset (if recommended): After updating, perform a factory reset and reconfigure the charger.
  • If E28 persists: One of the modules may have corrupted firmware beyond recovery and must be replaced (main control board or communication module).
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Repair Difficulty

Medium 3/5

Required Part

Walli communication module
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