Troubleshooting Kenmore Error Code F23: What It Means & How to Fix

The Kenmore Dryer Error F23 indicates that the **exhaust thermistor has shorted**. This sensor is responsible for monitoring the temperature of the air as it exits the drum. When it shorts out, the control board detects an abnormal electrical signal, essentially thinking the dryer is dangerously overheating, and shuts down the system to prevent a fire.

You might be noticing that your dryer starts for a few seconds and then abruptly stops with a series of beeps, or perhaps it refuses to heat at all, leaving your clothes damp and cold. It can be incredibly frustrating to see your laundry pile up, but don’t worry! This is a very common issue, and with a little bit of patience and some basic tools, you can absolutely fix this yourself and save a significant amount of money on a repair technician.

How to Fix Kenmore Error F23 (Step-by-Step)

I’m going to walk you through this process just like I was standing there in the laundry room with you. Take your time, and remember: safety is our number one priority!

1. Safety First – Power Down:

   Before you touch a single screw, unplug the dryer from the wall outlet. If it is a hardwired unit, turn off the dedicated circuit breaker in your home’s electrical panel. Never work on an appliance while it is connected to power; dryers use high-voltage electricity that can be fatal.

2. Access the Lower Front Panel:

   On most Kenmore Elite or HE models, the thermistor is located on the blower housing at the bottom front. Use your Phillips head screwdriver or a 1/4″ nut driver to remove the two or three screws located at the very bottom of the “toe panel” (the small panel under the door). Once the screws are out, pull the panel slightly toward you and drop it down to remove it.

3. Locate the Blower Housing:

   Look to the left side behind the panel you just removed. You will see a large white plastic or silver metal housing—this is the blower duct. Mounted directly onto this duct, you will find two small components. One is the thermal fuse (usually white and rectangular) and the other is the thermistor (usually a smaller, black or grey plastic piece with two wires plugged into it).

4. The Multimeter Test:

   Pull the two wires off the thermistor terminals (grip the plastic connectors, not the wires themselves). Set your multimeter to the “Ohms” (Ω) setting. Touch the probes to the two terminals on the thermistor. At room temperature (approx. 70°F), you should see a reading of about 10,000 ohms (10k). If the meter reads 0 ohms or very close to it, the part is definitely shorted and must be replaced.

5. Replace the Thermistor:

   Remove the one or two screws holding the old thermistor onto the blower housing. Pull the old part out and set it aside. Position your new thermistor (ensure it’s the exact OEM replacement part) and screw it into place. Ensure it sits flush against the housing so it can accurately sense the air temperature.

6. Reconnect and Reassemble:

   Plug the two wires back onto the terminals of the new thermistor. It doesn’t matter which wire goes on which terminal for this specific part. Replace the toe panel by sliding the top tabs into place first, then securing the bottom screws.

7. The Final Test:

   Plug the dryer back in. Select a “Timed Dry” cycle for 10 minutes and press start. If the dryer stays running and starts to produce heat without the F23 code appearing, you’ve successfully mastered the repair!

Technical Explanation of the Fault

To understand why your dryer is acting up, we need to look at the “brain” and the “nerves” of the machine. The exhaust thermistor is a Variable Temperature Resistor. Under normal conditions, its electrical resistance changes based on how hot the air is. The control board monitors this resistance to decide when to turn the heater on or off.

Why do these sensors fail? There are usually three main culprits:

1. Internal Component Degradation: Inside the thermistor is a ceramic semiconductor. Over years of constant heating and cooling (thermal cycling), the internal structure can physically crack or break down. This causes the resistance to drop to near zero, which the dryer interprets as a “short.”
2. Lint Accumulation and Overheating: If your dryer vent is clogged, the thermistor is subjected to extreme temperatures beyond its design specifications. This excessive heat can literally bake the internal components, causing them to fuse together and create a short circuit.
3. Wiring Harness Vibration: Dryers vibrate—it’s what they do. Over time, the wires leading to the thermistor can rub against the sharp metal edges of the dryer cabinet. If the insulation wears away and the “live” sensor wire touches the metal frame, it creates an external short that triggers the F23 code just as easily as an internal failure.
4. Voltage Spikes: Like any sensitive electronic component, a sudden surge in your home’s electrical system can “pop” the resistor inside the thermistor, leading to an immediate failure.

Symptoms of a Shorted Exhaust Thermistor

When your Kenmore dryer is struggling with an F23 error, it will usually “talk” to you through several distinct physical signs. Recognizing these early can help you confirm the diagnosis before you even pick up a screwdriver:

• The Display Flashes F23: This is the most obvious sign. The dryer will interrupt the cycle, stop spinning, and flash the code on the digital interface, often accompanied by a persistent beeping sound.
• Premature Shutdown: You might press “Start,” hear the motor engage for about 30 to 60 seconds, and then the unit simply gives up. The control board performs a safety check during startup; once it realizes the thermistor is shorted, it kills power to the heating element and motor.
• Cold or Lukewarm Air: Because the sensor is sending an incorrect “overheating” signal, the control board may refuse to engage the heating element at all as a failsafe, resulting in air that never gets warm.
• Inaccurate Drying Times: If the sensor is failing but not completely dead, you might notice the “Estimated Time Remaining” jumping wildly from 40 minutes down to 1 minute instantly.

How to Prevent Error F23

Now that you’ve fixed the problem, let’s make sure it doesn’t happen again! These sensors are sensitive, and a little maintenance goes a long way in protecting them.

1. Clean Your Exhaust Vent Annually: The number one killer of dryer sensors is heat buildup caused by lint. Even if you clean your lint screen every load, fine particles bypass the screen and clog the silver ducting behind the dryer and the vent leading outside. Buy a vent cleaning brush kit and clear the entire run at least once a year. This keeps the air flowing and the thermistor cool.

2. Use an Appliance Surge Protector: Since the F23 error can be caused by electrical shorts from voltage spikes, consider plugging your dryer into a high-quality surge protector designed specifically for heavy appliances. This protects the sensitive resistor inside the thermistor from “frying” during a storm.

3. Don’t Overload the Drum: Shoving too many wet towels into the dryer at once restricts airflow inside the drum. This causes the temperature near the blower housing to spike rapidly, putting unnecessary thermal stress on the thermistor and shortening its lifespan.

Frequently Asked Questions

Q: Can I just bypass the thermistor with a jumper wire to keep the dryer running?
A: Absolutely not. This is extremely dangerous. The thermistor tells the dryer when to shut off the heat. If you bypass it, the heating element could stay on indefinitely, reaching temperatures high enough to melt the internal components or start a house fire. Always replace the part; it’s a cheap safety device.

Q: Is the F23 error the same as the F22 error?
A: They are related but opposites. F22 usually means the thermistor circuit is “Open” (a broken wire or totally dead sensor), while F23 means it is “Shorted” (electrical path is bypassed or fused). However, the fix is almost always the same: replacing the thermistor itself.

Q: My multimeter shows 10k ohms, but I still see the F23 code. What now?
A: If the thermistor tests fine, you likely have a “short to ground” in the wiring harness. Inspect the wires leading from the sensor all the way up to the control board. Look for any spots where the wire insulation has rubbed off against the metal frame. If the wires look perfect, the issue might unfortunately lie in the main electronic control board, which would be the next item to replace.