On the covered LG range or oven, F1, F2, F4, F5 means an Upper Oven Thermistor Error — LG's own wording. First, record the code and stop the cooking function that produced it. Then: for F1, F2, F4 and F5 LG's first move is to press CLEAR/OFF and try the function again; if the code shows up again, the range's breaker goes off for 30 seconds and then back on — LG's own sequence.
Differential
Likely causes of “LG range or oven code F1, F2, F4, F5”, and how to tell them apart
- 1
An upper oven sensor that has drifted
What separates it The oven temperature is wrong and the code appears early in a bake
How to confirm The sensor probe inside the oven can be checked for resistance by a technician against LG's table
- 2
A damaged sensor wire or connector
What separates it The code appears intermittently, often after cleaning
How to confirm Look for a loose or scorched connector at the back with the power off
- 3
A sensor that has failed open or shorted
What separates it F16 shows as soon as the oven is switched on
How to confirm The code appears instantly rather than after heating
- 4
A fault on the control that reads the sensor
What separates it The sensor tests fine but the code returns
How to confirm A technician checks the sensor input on the electronic control
- 5
A sensor probe that has been bent or touched a rack
What separates it The oven runs hot or cool
How to confirm Check that the probe is straight and clear of the cavity wall
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the code is F1, F2, F4, F5 or F16
- Whether it appears immediately or after the oven heats
- Whether the oven runs hotter or colder than set
- Whether the oven was just cleaned
Try in this order
0 of 12 completedWhat to do first
ReversibleRecord the code and stop the cooking function that produced it.
Correct only the documented fault domain
ReversibleFor F1, F2, F4 and F5 LG's first move is to press CLEAR/OFF and try the function again; if the code shows up again, the range's breaker goes off for 30 seconds and then back on — LG's own sequence.
Press CLEAR/OFF and retry
ReversiblePress the CLEAR/OFF key and try the original function again; LG gives this as the first step for this code.
Reset at the breaker
ReversibleIf the code reappears, turn the circuit breaker to the unit off, wait 30 seconds and turn it back on.
Note the cavity
ReversibleRecord which cavity the code appeared in: F1 and F2 are the upper oven and F4 the lower, so the wrong cavity in the service call wastes a visit.
Schedule service
ReversibleIf the problem continues or the troubleshooting steps cannot be performed, LG says the unit will require service; use its Request a Repair page with the model number and the exact code.
Do the two-stage reset
ReversiblePress CLEAR/OFF, wait a moment and retry; if F1 comes back, turn the range's breaker off for 30 seconds.
Time the code
ReversibleStart a 350 degree bake and note whether the code appears at once, which suggests an open or shorted sensor, or after twenty minutes, which suggests drift.
Look at the sensor probe
ReversibleWith the oven cool and the breaker off, find the thin metal probe at the top rear of the cavity; it should stand straight, clear of the wall and any liner.
Compare with a thermometer
ReversiblePut an oven thermometer on the center rack for a bake. If the display and the thermometer disagree by more than 25 degrees, the sensor is reading wrongly.
Look at the connector behind the panel
ReversibleDo not pull wires. A scorched or loose connector at the rear is something to tell the technician, not to repair yourself.
Write down what you saw
ReversibleCode number, how soon it appeared, and the temperature error, so the visit starts with facts.
Model-specific
What is true of this model and not of its siblings
- What the sensor does
- It tells the control the true oven temperature, which is why a wrong reading ruins baking.
- Cause to rule out first
- A sensor probe bent against the liner or a rack pushed against the rear wall.
- What LG says
- LG gives the reset sequence for this family and then service if the code returns.
Stop boundary
When this stops being a self-service repair
- !Turn the circuit breaker off before any panel is opened or any wire is touched
- !Turn the oven off at the breaker before anyone touches the sensor or its wires
- !If the code returns after LG's reset, book service with the model number and the exact code
- !Do not use an oven that overheats or does not shut off
Evidence ledger
Sources behind this answer
Where the manufacturer's article stops. LG words these codes identically, so they share this page.
Exact questions
Common questions
What does F1, F2, F4, F5 mean on a LG range or oven?+
an Upper Oven Thermistor Error — LG's own wording.
What do F1, F2, F4 and F16 mean on an LG range?+
Thermistor or oven sensor errors; F1 and F2 upper oven, F4 lower oven, F16 an oven sensor issue.
What is a thermistor?+
The temperature sensor the control uses to regulate the oven.
Why does the sensor error appear the moment I switch the oven on?+
An instant code usually means the sensor circuit is open or shorted, so the control cannot read a temperature at all. A code that waits until the oven heats suggests the sensor drifting.
Is the sensor an expensive part?+
The probe itself is among the cheaper oven parts, and on many LG ranges it comes out with a couple of screws behind the rear panel; the cost is mostly the visit and the care needed to work safely.
Why would the oven run too hot with a thermistor error?+
The control adds heat until the sensor says it is warm enough. A sensor reading low makes the oven overshoot, which is why an oven that burns food and then shows a code should not be used.
Can I still use the cooktop?+
Yes, the cooktop is a separate circuit, but do not use an oven that overheats or does not shut off.
Is the sensor error with the higher number a different fault?+
LG words F1, F2, F4, F5 and F16 alike as an upper oven thermistor error, so they share this page.