E18
Polestar External Load Management Communication Fault

Charger shows E18; load balancing with other chargers or home energy system does not function.

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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

Disconnected or damaged RS‑485/CAN bus cable, Incorrect load management address or ID, Failed external load controller, Faulty communication port on Polestar charger

How to Fix / Troubleshooting

Safety first: Turn off power to all interconnected chargers before working on communication wiring.

  • Inspect bus wiring: Trace the RS‑485 or CAN cable between the Polestar charger and any external load controller or additional chargers. Look for loose terminals, broken conductors, or incorrect polarity.
  • Verify termination: Ensure that bus termination resistors are installed only at the ends of the communication line as specified by Polestar.
  • Check addressing: Using the installer menu or app, confirm that each charger has a unique address/ID and that the controller is configured to recognize them.
  • Port test: If other devices on the bus communicate correctly but this charger shows E18, the communication port on the charger’s main control board may be defective and require replacement.
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Repair Difficulty

Hard 4/5

Required Part

Polestar RS‑485/CAN Interface
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