Charger displays E09, Wi‑Fi or Ethernet LED may be off, remote control via app fails.

Safety first: Communication faults are usually low‑voltage but still isolate mains before opening the housing.

• 1. Power cycle the charger:
  • Turn off the breaker for 60 seconds and turn it back on.
  • Observe if communication LEDs on the communication module light up.
• 2. Check physical connections:
  • Open the housing and locate the plug‑in communication board (Wi‑Fi/Ethernet/Modbus).
  • Reseat the board by unplugging and firmly plugging it back into the main control board.
  • Inspect the Ethernet jack for bent pins or corrosion.
• 3. Verify network cabling:
  • Test the Ethernet cable with another device or replace it.
  • Ensure the router/switch port is active.
• 4. Firmware check:
  • If accessible, log into the charger’s web interface and verify firmware versions.
  • Update firmware only using Heidelberg‑approved files and procedures.
• 5. Replace module if needed:
  • If E09 persists and the module shows no activity, replace the communication module with the correct Heidelberg spare part.