Viking Refrigerator Error Code E3: Evaporator Thermistor... | appliancefaults.com

Technical Background:

The MCU (Microcontroller Unit) on the main control board monitors the evaporator thermistor's resistance. This resistance corresponds to a temperature. If the MCU detects a reading outside the acceptable range, or no reading at all (open circuit), it triggers the E3 error. The thermistor usually operates on a 5V DC circuit.

Symptoms:

Homeowners often report the freezer or refrigerator not maintaining proper temperature. An error code E3 is displayed on the control panel. The unit might be cycling more frequently than usual, or not at all.

Possible Causes:

Faulty evaporator thermistor.
Wiring harness issue between thermistor and control board.
Loose connection at the thermistor or control board.
Defective main control board.
Excessive frost buildup impacting thermistor readings.

Solution:

1

Turn off the refrigerator at the breaker panel (LOTO - Lock Out Tag Out).
2

Locate the evaporator thermistor. This is generally behind the rear panel inside the freezer. You'll need a 1/4-inch nut driver to remove the panel screws.
3

Visually inspect the wiring and connector. Look for broken wires or corrosion.
4

Disconnect the thermistor and measure its resistance using a digital multimeter. Compare this to the thermistor's temperature/resistance chart (available in the service manual or online). For example, at 32°F, a typical thermistor might read 10k ohms.
5

If the thermistor is good, check the wiring harness continuity from the thermistor to the main control board connector. Use your multimeter set to Ohms. You should see close to 0 ohms.
6

If the wiring and thermistor are good, suspect a faulty main control board. Replacement might be necessary. Measure the voltage at the thermistor connector on the main board. It should be around 5V DC.
7

Reassemble and restore power. Monitor for error code reappearance.

Safety Warning:

Always disconnect power to the appliance at the breaker panel before performing any repairs. This appliance operates on 120V AC. Failure to disconnect power can result in serious injury or death. Observe Lock Out Tag Out (LOTO) procedures.

Prevention:

Regularly defrost the freezer to prevent excessive frost buildup, which can affect the thermistor's readings. Inspect the door seals to ensure a tight seal, minimizing moisture entry.

Expert Tip:

Many Viking refrigerators have a service mode. Entering this mode allows you to directly read the thermistor value on the display, bypassing the error code logic. Consult the service manual for the specific key sequence to enter service mode for your model.

Follow-up Questions:

Frequently Asked Questions

•What is the typical resistance value of the evaporator thermistor at room temperature (70°F)?

The typical resistance value varies depending on the thermistor type, but at 70°F, it's usually between 2k and 5k ohms. Refer to the service manual for the specific value for your model.

•How do I access the main control board in this Viking refrigerator model?

The main control board is typically located behind a panel on the rear of the refrigerator. You'll likely need to remove the back panel with a 5/16-inch socket or a nut driver. Disconnect power before accessing.

•If the thermistor resistance reading is intermittent, what should I check?

Check the thermistor connector pins for corrosion or looseness. Also, inspect the wiring harness for any signs of damage or breaks. Gently wiggle the wires while monitoring the resistance reading to see if it fluctuates.

Viking Refrigerator Error Code E3: Evaporator Thermistor Failure Troubleshooting

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip:

Frequently Asked Questions

•What is the typical resistance value of the evaporator thermistor at room temperature (70°F)?

•How do I access the main control board in this Viking refrigerator model?

•If the thermistor resistance reading is intermittent, what should I check?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Expert Tip: