Step-by-Step DIY Fix Guide
- SAFETY: Turn off the oven immediately and wait for it to cool completely (at least 1 hour).
- Disconnect power for 60 seconds, restore, and test.
- If F5 returns, test the lower oven sensor with a multimeter — at 70°F it should read approximately 1080–1090 ohms. A significantly lower reading indicates a short.
- Replace the sensor if shorted. If the sensor tests good, call a technician — the control board relay may be sticking.
If the warning comes back after restart
- If the warning returns immediately after a clean restart, the sensor or wiring path becomes more likely than a one-time glitch.
- F5 appears during a normal bake cycle and the lower oven sensor reads within specification
What This Error Means
Error F5 on your LG oven means: The lower oven temperature sensor is reading a shorted condition or the lower oven cavity has exceeded a safe operating temperature. The range's self-diagnostic system has detected this condition.
The most frequent cause is lower oven thermistor shorted — resistance too low. Work through the causes and fix steps below in order — many LG oven errors are resolved without a service call.
Many cases of F5 can be resolved by the homeowner. The steps below cover the full DIY checks — if they do not resolve the error, a technician is needed.
Oven temperature sensor faults are among the most common LG oven errors. The sensor is a simple probe on the back wall of the oven cavity — reconnecting a loose harness connector resolves around half of all sensor fault codes. Sensor replacement is a 15-minute DIY repair when the connector check does not resolve it.
What users usually notice before this code
LG oven warnings like this often appear after interrupted heating, control resets, sensor mismatch, or a fault that returns during warm-up rather than during a stable cook cycle.
Common misdiagnoses
- Assuming the display code proves one exact failed part before the safe first checks are done.
- Treating a sensor-related warning as a guaranteed board failure before checking the simpler model-family causes first.
- Restarting the appliance repeatedly instead of confirming whether the same fault returns after one clean recovery attempt.
Most Likely Cause by Symptom
The LG oven may stop, pause, or refuse to complete the cycle normally.
Likely cause: Lower oven thermistor shorted — resistance too low
Check first: SAFETY: Turn off the oven immediately and wait for it to cool completely (at least 1 hour).
The warning may return immediately because the appliance is detecting an internal fault.
Likely cause: Lower oven overtemperature event during self-clean
Check first: Disconnect power for 60 seconds, restore, and test.
Common Causes
- Lower oven thermistor shorted — resistance too low
- Lower oven overtemperature event during self-clean
- Control board relay sticking and applying continuous power to the lower bake element
What Not to Do
- Do not restart the oven immediately after F5 — allow 1 hour to cool before investigating
Model and Display Variation Notes
Model-family notes
- LG oven display wording and code formats can vary by series.
- If your model behaves differently, check the owner manual before trying any deeper maintenance step.
Display and panel differences
- Panel wording can vary by series, so confirm the exact code pattern before buying parts.
Parts, Tools and Service Options
Service option
LG service visit if the warning returns after the basic checks are complete.
Manual and model check
Check your exact model and manual before ordering any LG oven parts.
Common parts
- Lower oven temperature sensor/thermistor if sensor is shorted ($15–$40)
- Main control board if bake relay is sticking ($100–$250)
This section stays service-first because the page points more strongly toward support or professional repair than a routine parts purchase.
When Not to Keep Troubleshooting
F5 appears during a normal bake cycle and the lower oven sensor reads within specification
How to Prevent It Recurring
- Allow the oven to cool fully between self-clean cycles — consecutive self-clean runs stress the lower oven sensor
Related Error Codes
F4
The lower oven cavity temperature sensor (thermistor) is reading an open circuit on double-oven models. The lower oven cannot monitor temperature and the lower cavity is disabled.
F2
The upper oven temperature sensor has detected a temperature that is dangerously high, or the sensor is reading a shorted condition that makes the oven's control board believe the temperature is above a safe threshold.
F19
LG oven error F19 usually means the oven can heat up, but it is not maintaining the set temperature reliably.
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When not to keep pushing DIY troubleshooting
If the same warning returns after the first safe checks, or the next step would require invasive disassembly, stop there and move to model-specific guidance or service.
Extra notes
- This page is based on LG support material and stays conservative where model-specific guidance may vary.
- The goal is to help you identify safe first checks before you move into parts, service, or model-specific manual lookup.
Source and model notes
Last reviewed: 2026-04-08
Based on: Based on LG support material and edited into consumer-safe guidance for the exact code family on this page.
Model coverage note: LG oven code meanings can vary by series, control panel, and model family, so use this page as a safe starting point rather than a replacement for the model-specific manual.
Important: FixThisError is an independent guide, not the manufacturer. Use your model-specific manual when the panel wording or behavior differs.
Always disconnect power before inspecting appliances. If unsure, contact a licensed appliance technician.