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LG Dryer Error Code F9

Reviewed by the ApplianceErrors Editorial Team · Verified against manufacturer service documentation · Last verified: June 10, 2026
⚠ Medium Severity 🔧🔧 Moderate DIY Also shown as: E1

Thermistor failure — temperature sensor not reading

The most common cause of the F9 error on a LG dryer is thermistor open circuit (burned out) (~60% of cases); start with: test the thermistor.

💰 DIY cost: $15–$35 👨‍🔧 Pro cost: $150–$280 Save $135+ by doing it yourself
LG Dryer error code F9 on the display panel
How the F9 code appears on a LG dryer display

What Does Error Code F9 Mean on a LG Dryer?

Thermistor failure — temperature sensor not reading.

F9 (also shown as E1) fires when the control board reads the thermistor's resistance as out of range — typically an open circuit, a short, or a value that never changes as the drum heats. Because the board relies on this sensor to regulate heat safely, it halts or limits heating rather than risk overheating. Unlike a clogged-vent or high-limit fault, F9 points to the sensor's electrical reading itself, not to actual excessive temperature or airflow restriction.

Models affected: LG electric and gas dryers with a duct-mounted thermistor, including models such as DLEX3900W, DLE3500W, DLEX4500B, DLE7150W, and DLG3601W
What owners report: Owners commonly report this code appearing at the start of a cycle or shortly after heating begins, sometimes with clothes coming out damp. A loose or corroded connector at the sensor is a frequent false trigger, and reseating it is the quick win many people mention before replacing the part.

What Causes Error Code F9?

Here are the most common causes in order of frequency. Start with the most likely cause before moving to the next:

  1. 1
    Thermistor open circuit (burned out) 60% of cases
  2. 2
    Thermistor connector loose 25% of cases
  3. 3
    Wiring harness damaged 15% of cases

How to Fix LG Dryer Error Code F9

🔧🔧 Moderate DIY Est. time: 30–60 min
⚡ Safety first: Unplug the appliance before opening any panels or touching internal components.
  1. 1

    Test the thermistor

    The thermistor is usually on the exhaust duct inside the dryer. At room temp, test resistance: ~10k ohms expected.

    🔩 Multimeter
  2. 2

    Check connector

    Reseat the connector at the thermistor.

  3. 3

    Replace thermistor

    A simple pull-and-click replacement if the sensor is accessible.

    🔩 LG dryer thermistor ($15–$35)
    ⚠️ Unplug dryer first.

How to Reset Error Code F9

After repair, unplug for 1 minute then restart. Code clears after a successful cycle.

Note: If the error returns after resetting, the underlying issue has not been resolved. Work through the fix steps above.

Full LG dryer reset guide → Enter diagnostic mode →

Did this guide fix your appliance?

When to Call a Professional

If thermistor is new and error continues, the control board thermistor input is faulty.

Average professional repair cost for this issue: $150–$280

Same Code on Other Brands

Error code F9 appears on these other brands too. See every brand that shows F9 →

Whirlpool logo
Whirlpool Oven F9
Door latch fault — self-clean lock circuit
GE Appliances logo
GE Appliances Oven F9
Door latch failure — self-clean lock not completing

Find Replacement Parts

Use these links to find the exact replacement parts for your LG Dryer:

🔩
Search PartSelect
LG Dryer repair parts
🔧
Search RepairClinic
Step-by-step video guides

External links — ApplianceErrors.com is not affiliated with these retailers.

More LG Dryer Error Codes

D80 Duct blockage detected — exhaust duct 80% blocked D90 Duct blockage detected — exhaust duct 90% blocked D95 Duct blockage detected — exhaust duct 95% blocked CL Child lock is active — controls are locked nP No power to the heating element D75 Exhaust duct ~75% blocked — airflow restriction warning

Frequently Asked Questions

Can I keep using my LG Dryer when error F9 appears? +
You often can for a cycle or two, but the sensor issue behind F9 will keep interrupting normal operation until it is fixed. Plan the repair rather than ignoring the code.
What most commonly causes F9 on a LG Dryer? +
Across reported LG dryer repairs, the most frequent is thermistor open circuit (burned out) (60% of cases), thermistor connector loose (25%), then wiring harness damaged (15%). Check them in that order before replacing any parts.
F9 keeps coming back after a reset — what should I check next? +
A reset only clears the stored F9 fault; if it returns, the sensor problem is still present. Move on to the physical checks — test the thermistor, then check connector — since the code will reappear until the root cause is resolved. This is a moderate job — a multimeter and some disassembly are usually involved.
How much does it cost to fix LG Dryer error F9? +
A DIY repair typically runs $15–$35 in parts, versus $150–$280 for a professional service call, so handling it yourself saves around $135. Expect the work to take roughly 30–60 minutes.
Which LG Dryer models show error F9? +
F9 is documented on LG electric and gas dryers with a duct-mounted thermistor, including models such as DLEX3900W, DLE3500W, DLEX4500B, DLE7150W, and DLG3601W. Other units sharing the same control platform can display it too, so the fixes here generally transfer across the series.

Sources & References

Content verified against manufacturer service documentation. Last verified: June 10, 2026.

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