Charger shows E04; vehicle does not detect charging station or shows communication error.

Safety first: De-energize the charger before opening. Communication circuits are low voltage but are adjacent to mains components.

• Test with another EV: If possible, connect a different vehicle to rule out a car-side fault. If the second vehicle charges normally, the issue is likely with the first EV.
• Check cable and socket: Inspect the CP pin and surrounding insulation for damage or contamination. Clean gently if needed.
• Verify configuration: For Mennekes chargers with configuration dials or DIP switches (e.g., to set max current), confirm that settings match the installation (e.g., 1-phase vs 3-phase, 16 A vs 32 A). Incorrect settings can cause PWM mismatch.
• Control board diagnostics (qualified person): Use the service manual to check diagnostic LEDs or test points for CP PWM presence. If no PWM is present or the duty cycle is incorrect, the main control PCB may need replacement.
• Firmware update: If supported, connect via the Mennekes service interface and check for firmware updates that address communication issues.

If configuration and wiring are correct and multiple vehicles fail to charge, arrange for control board replacement by an authorized service provider.