The F28 fault code means failed communication between the main control board and the motor control board. It happens because of the following things:
- Faulty motor control board.
- Faulty main control board.
- The micro switches in the washer cabinet are not grounded properly. Therefore, running the machine with the front bottom service panel removed will result in the code flashing on the display. This also happens due to faulty switches and wiring.
- Bad wiring between the two units.
- Faulty or damaged wiring harness.
- Faulty drive motor or part of it.
Disconnect your washer from the mains and inspect the wiring between the two control boards. Do not disassemble the device without unplugging it and use protection tools!
Check the wire harness between the two units. Make sure that all grounding switches are engaged (one on the front and one on the back). Loose grounding connection is a common cause of the F28 fault code.
IMPORTANT: Be sure that the bottom front panel is fixed and engages the front grounding switch properly.
Check the power cord and the connection on the line filter. The black wire (L1) should be connected to the L terminal, and the white one (Neutral) – to the N terminal, not vice versa!
Make sure the MI3 Serial Communication Connector in the machine control unit is not upside down, and the wires are on the left of the unit’s connectors. Also, check the RRAST connectors. Make sure the pins are not deformed, and the connections are not loose. It is recommended to remove the connector and check it closely.
If you have a technical experience with this kind of washer, you can do all these steps. Use ohm and volt meters to test all parts and connections. Welcome to join the discussion and share your troubleshooting ideas concerning this particular issue!