Mitsubishi Air Conditioner Error Codes
Mitsubishi 4121 Error Code
1. Error code definition
Function setting error
2. Error source, cause, check method and remedy
Cause Check method and remedy
(1) Fan motor connector contact failure Check the fan motor connector CNMF for proper connection.
(2) Contact failure of the relay connector for the fan motor
Check the relay connector for the fan motor for proper connection.
(3) Indoor unit circuit board failure Remove the fan motor connector CNMF and check the voltage at the
indoor unit circuit board. Testing point 1. 280 VDC (Between CNMF1 (+) and CNMF4 (-))
2. 15 VDC (Between CNMF5 (+) and CNMF4 (-) Replace the indoor unit circuit board if the voltage is abnormal.
If the 4114 error persists after the indoor unit circuit board is replaced, replace the fan motor as well.
(4) Fan motor fault Replace the fan motor if the voltage is normal in step (2) above.
If the 4114 error persists after the fan motor is replaced, replace the indoor unit circuit board as well.
Cause Check method and remedy
(1) Board failure Replace the board.
(2) Motor malfunction Check for the motor and the solenoid switch.
(3) Solenoid switch malfunction Error source Cause Check method and remedy Outdoor unit (1) Dip switch setting error on the control board Check the SW6-1 setting on the control board
(2) Connector connection error on the control board Check that nothing is connected to the connector CNAF on the control board.
(3) Control board failure Replace the control board if no problems are found with the two items above
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