Charger displays E03 and refuses to start; vehicle may show ‘Check power source’.

Safety first: Only qualified persons should work inside the distribution board. Always isolate at the main breaker before testing.

• Step 1 – Confirm supply rating: Check the Jaguar wallbox rating label (e.g., 230 V single-phase or 400 V three-phase). Ensure the supply matches the required configuration.
• Step 2 – Measure line voltage: With a multimeter and appropriate PPE, measure voltage at the charger’s supply terminals (L–N or L–L). It must be within Jaguar’s specified range (typically ±10%). If outside, contact an electrician or utility provider.
• Step 3 – Inspect terminations: With power OFF, tighten all line, neutral, and earth terminals in the charger and in the upstream isolator. Look for discoloration or melted insulation indicating overheating.
• Step 4 – Check neutral continuity: Ensure neutral is present and correctly connected for single-phase units. A missing neutral can trigger E03.
• Step 5 – Internal PCB check: If supply is stable and wiring is correct, but E03 persists, the input sensing circuit on the Jaguar wallbox control PCB may be faulty. Do not bypass protections; arrange for PCB replacement by an EVSE technician.