Whirlpool Washer Error Code 355

Error code 355 indicates an Evaporator Thermistor Fault on the NTC 2 sensor, meaning the thermistor reading is outside the expected range. This sensor is part of the heat pump system and monitors evaporator coil temperature. The control board cannot verify proper thermal conditions, so the unit stops the cycle to prevent damage. Diagnosing this fault starts with running service mode test 15, the Heat Pump System Test.

A reset may temporarily clear the code, but if the underlying fault with the NTC 2 thermistor or its wiring remains, the error will return when the machine attempts to run the heat pump system again. Resetting without diagnosis does not fix the root cause. It is best to complete the full heat pump system test before assuming the issue is resolved.

Repair costs depend on what component has failed. Replacing the NTC 2 thermistor alone is generally the least expensive repair, with parts typically ranging from $15 to $60 and labor adding $75 to $150 depending on your area. If the control board or a heat pump component is responsible, total repair costs could range from $200 to $500 or more. Getting a diagnostic visit before authorizing parts replacement helps avoid unnecessary expenses.

Some steps are DIY-friendly, such as checking for loose or corroded connectors at the thermistor and inspecting the wiring harness for visible damage. However, running service mode test 15 and performing accurate resistance testing of the NTC 2 thermistor requires familiarity with appliance diagnostics and a multimeter. Heat pump component repairs, including thermistor or control board replacement, are generally within reach for experienced DIYers but may warrant a technician if the heat pump system itself is involved.

Running the machine while this fault is active is not recommended. The control board cannot monitor evaporator temperature correctly, which means the heat pump system is operating without proper thermal feedback. Continuing to run cycles under this condition could cause additional stress on heat pump components or result in incomplete cycles.