Charger displays E16 or ‘isolation error’; unit refuses to start charging for safety reasons.

Safety first: An isolation fault can indicate a serious shock risk. Do not ignore this error.

• Inspect environment: Check for signs of water ingress around the Webasto housing, conduit entries, and cable glands.
• Drying period: If moisture is suspected, switch off power and allow the unit to dry for 24–48 hours in a dry environment before retesting.
• Check seals: Ensure all cable glands and covers are properly tightened and gaskets are intact.
• Professional testing: A technician should perform insulation resistance tests on internal wiring and components, and verify the IMD operation.
• Replace faulty parts: Any compromised wiring or a defective IMD must be replaced with Webasto-approved components.