Porsche EV home charger shows E03 and does not energize; charging session will not start.

Safety first: Grounding faults are serious. Do not bypass earth connections. Turn off power at the main breaker feeding the charger before inspection.

• Check supply earth connection: Have a qualified electrician open the wallbox front cover and verify that the green/yellow PE conductor is securely clamped in the earth terminal block and that the terminal screws are tight.
• Inspect for corrosion or overheating: Look for discoloration, melted insulation, or corrosion on the earth terminal and surrounding conductors. Replace any damaged wiring and clean terminals as needed.
• Verify building earth: The electrician should test the building’s earth system and continuity from the main panel to the Porsche wallbox. Correct any upstream grounding issues.
• Internal earth monitor check: If wiring is correct, the technician should test the earth monitoring circuit on the main control PCB according to Porsche service documentation. Replace the main control board if the circuit is defective.
• Re-test operation: After corrections, restore power and attempt a short charging session while monitoring for recurrence of E03.