Amana Dryer Error Code 4

Error code 4 on an Amana dryer indicates a possible motor transistor fault detected during startup. Specifically, the machine control board's internal diagnostics have identified that the motor transistor, which is responsible for switching power to the drive motor, appears to be either open (not conducting) or shorted (conducting continuously) at the moment the control board attempts to energize the motor circuit. This detection happens during the startup sequence before normal operation begins, and it reflects a condition the control board monitors as part of its self-check routine.

The motor transistor is a solid-state switching component integrated into the machine control board. It acts as the electronic gate that allows the board to command motor operation. When this transistor fails open, the motor receives no signal and will not start. When it fails shorted, unintended current can flow through the motor circuit, which can cause operational faults or even damage. Because this component is part of the control board assembly, it cannot be serviced independently and a board failure means the entire control board must be replaced.

Before assuming the control board has failed, loose or corroded connections in the motor circuit can cause the board to incorrectly read the transistor as open or shorted. The recommended first step is to inspect all wiring harness connections in the motor circuit for looseness, corrosion, or damage, and then run the System Check Mode to test the motor relay function. If the motor relay functions correctly during System Check Mode, the error code can be disregarded as a false trigger. If the relay does not function, the machine control board requires replacement.