E109
Enphase Pilot Line Short Circuit

Charger shows E109; app may indicate 'Pilot short to ground' or 'Pilot short to line'.

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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

Crushed or pinched pilot conductor in cable, Water ingress causing pilot-to-ground short in connector, Internal short on pilot driver circuit, Contamination or conductive debris in J1772 connector

How to Fix / Troubleshooting

Safety: A pilot short can prevent safe communication with the vehicle. Turn OFF the breaker before inspection.

  • Inspect the connector: Look inside the J1772 handle for metallic debris, bent pins, or signs of arcing. Do not insert tools into the connector; gently tap out loose debris if visible.
  • Check cable routing: Ensure the cable is not pinched in a door, under a tire, or wrapped tightly around sharp edges. Any visible crushing or deep kinks require cable replacement.
  • Dry the connector: If the connector has been exposed to heavy rain or washing, allow it to dry thoroughly indoors for 24 hours.
  • Test again: Restore power and plug into the vehicle. If E109 persists, the pilot conductor or driver circuit is likely damaged.
  • Service: Replace the charge cable/handle assembly. If a new cable does not resolve the issue, the control board pilot driver must be replaced by a technician.
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Repair Difficulty

Medium 3/5

Required Part

Enphase EVSE Charge Cable Pilot Conductor / Control Board Pilot Driver
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