E304
Enphase
Internal CAN / Serial Bus Communication Fault
Charger shows E304; app may indicate 'Internal communication error' between control and power 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
Loose internal harness between control and power boards, Electrical noise disrupting internal bus, Failed transceiver on control board, Failed transceiver on power module
How to Fix / Troubleshooting
Safety: Internal access exposes high-voltage components. Only trained personnel should open the unit.
- Power cycle: Turn OFF the breaker for 5 minutes, then ON. Many transient bus errors clear after a full reset.
- Environmental check: Ensure no high-power RF or industrial equipment is installed very close to the charger that could induce noise.
- Technician inspection: A service technician should open the charger, reseat internal communication harnesses, and inspect for pin damage or corrosion.
- Board replacement: If communication remains unstable, replace the control board, power module, or both as indicated by diagnostics.
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Repair Difficulty
Professional Required
5/5
Required Part
Enphase EV Charger Control Board–Power Module Communication Harness
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