E105
Enphase
Main Contactor / Relay Weld Detection Fault
Charger shows E105 and does not start; app may indicate 'Contactor fault' or 'Relay weld detection'.
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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
Welded main contactor contacts, Failed contactor coil, Faulty contactor driver on control board, Incorrect feedback from contactor position sensing circuit
How to Fix / Troubleshooting
High-voltage hazard: The main contactor switches full line current. Do not open the charger enclosure unless you are a qualified technician. Turn OFF the breaker and leave it OFF until inspected.
- Power cycle: Turn the breaker OFF for 5 minutes, then ON. If E105 immediately reappears, assume a contactor or control fault.
- Listen for contactor click: When plugging in the vehicle (with breaker ON), you should normally hear a distinct click from inside the charger. No click or a repeated clicking pattern suggests a contactor or driver issue.
- Do not attempt to bypass: Never jumper or bypass the contactor; this defeats safety isolation and can cause fire or shock.
- Service action: A technician should open the unit, test the contactor coil resistance, inspect for welded contacts, and verify the contactor feedback circuit. Replace the main contactor assembly or control board as indicated by testing.
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Repair Difficulty
Professional Required
5/5
Required Part
Enphase EV Charger Main Contactor Assembly
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