Display shows E09; charger may start briefly then stop; vehicle reports ‘Insulation Fault’ or ‘Isolation Error’.

Safety first: Disconnect power at the breaker. Do not operate the charger if an insulation fault is suspected.

• Check for moisture ingress: Inspect the bottom and cable entry points of the Polestar charger for signs of water, condensation, or corrosion. If moisture is present, identify and correct the source (e.g., failed gasket, incorrect mounting) and allow the unit to dry completely.
• Inspect internal wiring: With the cover removed, look for damaged insulation, pinched wires, or carbon tracking on the internal harness and power module. Replace any damaged harness sections with Polestar‑approved parts.
• Dry the connector: If the vehicle connector has been exposed to rain or washing, dry it thoroughly and store it in its holster when not in use.
• Professional testing: If E09 persists after drying and visual inspection, a technician should perform insulation resistance tests and verify the operation of the internal insulation monitoring circuit. Replace the IMD or main control board if defective.