Charger shows E04 and does not energize the vehicle, often after a power event.

Safety first: Turn off the supply at the breaker and verify isolation. Contactor work must be done by a competent person.

• Listen for contactor operation: When starting a charge (before the error appears), you should normally hear a click from the internal contactor. If E04 appears without a click, the contactor may be stuck or the coil not energizing.
• Inspect contactor: With power OFF and cover removed, locate the main power contactor (usually a DIN‑rail mounted device). Check for signs of overheating, discoloration, or melted plastic.
• Check mechanical movement: Gently press the contactor armature (if accessible) to see if it moves freely. A jammed mechanism indicates the contactor should be replaced.
• Verify auxiliary feedback: Many Garo chargers use an auxiliary contact on the contactor for position feedback. Ensure the auxiliary wiring is secure and the contact block is firmly attached.
• Replace if necessary: If the contactor is welded or mechanically damaged, replace it with a Garo‑approved contactor of the same rating and coil voltage. Incorrect substitution can be dangerous.