E20
Hyundai NVRAM / Configuration Memory Fault

E20 appears and the charger indicates an internal memory or configuration error.

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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 non‑volatile memory on control board, Excessive write cycles to configuration storage, Failed EEPROM/Flash chip, Incomplete configuration during installation

How to Fix / Troubleshooting

Safety first: This is a low‑voltage issue; do not open mains compartments.

  • Factory reset: Use the Hyundai charger’s documented procedure (button sequence or app command) to perform a factory reset. Note that this may erase custom settings.
  • Reconfigure: After reset, re‑enter installation parameters (current limit, phase configuration, access control) using the app or installer interface.
  • Firmware refresh: If supported, reinstall or update firmware to rewrite configuration structures.
  • If E20 returns after reset: The NVRAM or control board is defective and should be replaced.
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Repair Difficulty

Medium 3/5

Required Part

Main Control Board (NVRAM)
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