Whirlpool Dryer Error Code 4

Error code 4 on a Whirlpool dryer signals a possible motor transistor fault detected during startup. The control board checks the motor transistor and flags this code if the transistor appears open or shorted. It can result from loose wiring connections or a failed machine control board. Running the System Check Mode will confirm whether the board needs replacement.

You should not attempt to run the dryer while this code is active and unresolved. A shorted motor transistor can allow uncontrolled current to reach the drive motor, potentially causing further damage. Have the motor relay tested via System Check Mode before resuming normal use.

If the issue is simply loose wiring connections, there is no parts cost and the repair is inexpensive. If the machine control board needs replacement, parts alone typically range from around $100 to $300 or more depending on the model, with additional labor costs if a technician performs the work. Getting a diagnostic visit from a technician before purchasing parts is recommended to confirm the board is at fault.

Start by checking all wiring connections in the motor circuit for looseness or corrosion, which is a straightforward task for a confident DIYer. If connections look good, accessing the System Check Mode requires familiarity with dryer diagnostics and is better suited to a technician. If the motor relay fails during that test, replacing the machine control board is the required fix and involves working with internal electrical components.

A power reset may temporarily clear the code if the fault was a transient startup irregularity. However, if the motor relay fails during System Check Mode, the code will return and a reset will not resolve the underlying problem. Proper diagnosis using the System Check Mode is the only reliable way to determine whether the code can be safely disregarded.