Charger displays E004 and immediately stops or refuses charging; relay click may not be heard.

Danger: A welded contactor can leave the output energized unexpectedly. Isolate power at the breaker before any work.

• Listen for contactor operation: During start-up, you should normally hear a distinct click from the internal main contactor. If E004 appears with no click, the contactor may be stuck or not being driven.
• Visual inspection: With power off and cover removed, inspect the ABB main contactor for discoloration, melted plastic, or signs of overheating.
• Manual test (technician): A qualified technician can test coil resistance and manually actuate the contactor (if design allows) to check for mechanical binding.
• Check control signals: Verify that the control board is sending the correct coil voltage when a charge session is requested. If the board is not driving the coil, the fault may be on the control board.
• Replace defective part: Replace the main power contactor or relay module with the ABB-specified replacement. If the relay is integrated on the power board, replace the entire power board assembly.