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Error code reference

LG Microwave Error Code E-45

Easy/PH sensor cooling error

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Easy/PH sensor cooling error - sensor voltage maintained over 3V continuously during initial cooking for 3 minutes.

First step from the service manual

Remove moisture from sensor and restart (open door for 5 minutes).

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E-45 means on a LG microwave

The E-45 error code on an LG microwave indicates a fault with the Easy or PH (humidity/steam) sensor cooling system. Specifically, the sensor's output voltage has remained above 3 volts continuously for 3 minutes during the initial phase of a cooking cycle. This sensor is designed to detect humidity or steam produced by food during cooking, and its output voltage is expected to fluctuate as conditions change inside the cavity. When the voltage stays elevated and does not drop below the 3V threshold within the allotted time window, the microwave interprets this as an abnormal sensor condition and triggers the E-45 fault.

The most frequent cause of this error is moisture contamination on or around the sensor itself. Condensation can accumulate on the sensor surface, especially if the microwave was used to heat liquids or high-moisture foods repeatedly without adequate ventilation between cycles. This trapped moisture artificially elevates the sensor's output signal, causing the control board to register a continuous over-voltage condition. This is why the first recommended diagnostic step is simply opening the microwave door for approximately 5 minutes to allow the sensor and surrounding cavity to dry out before attempting another cooking cycle.

If the error persists after the moisture-clearing procedure, the fault may indicate a degraded or failed sensor, damaged wiring between the sensor and the control board, or in less common cases, a problem with the control board itself misreading the sensor input. Technicians should verify the sensor's output voltage under normal conditions and inspect wiring harnesses for corrosion, pinches, or broken connections before condemning individual components.

Source: manufacturer service documentation.

Common causes of E-45

  1. 01

    Moisture or condensation on the sensor

    Wiring / connection

    Steam or condensation from cooking can coat the sensor surface and keep its output voltage artificially elevated above the 3V threshold. Opening the door for 5 minutes to dry the sensor is the first step and resolves this in many cases.

  2. 02

    Sensor positioned in a high-humidity environment

    Wiring / connection

    If the microwave is installed near a stovetop, dishwasher, or in a steam-prone area, ambient humidity can affect sensor readings even before cooking begins. Improving ventilation around the unit may prevent recurrence.

  3. 03

    Failed or degraded humidity sensor

    Part replacement

    Over time, the sensor element can degrade and output an inaccurate or continuously high voltage signal regardless of actual conditions inside the cavity. If drying the sensor does not resolve the error, the sensor may need to be replaced.

  4. 04

    Damaged or corroded wiring harness

    Part replacement

    Corrosion, pinched wires, or broken connections in the wiring between the sensor and the control board can cause a false high-voltage signal to be reported. Inspect the harness and connectors for visible damage or oxidation.

  5. 05

    Faulty control board

    Part replacement

    In rare cases, the control board may be misinterpreting the sensor's input signal even when the sensor itself is functioning correctly. This is typically diagnosed only after the sensor and wiring have been confirmed good.

See the test procedure for each cause

Frequently asked questions about E-45

What does E-45 mean on a LG microwave?
E-45 indicates a cooling error related to the Easy or PH humidity sensor. The sensor's output voltage has stayed above 3 volts continuously for 3 minutes during the start of a cooking cycle, which tells the microwave that something is abnormal with the sensor signal. This is most commonly caused by moisture or condensation on the sensor. Opening the microwave door for about 5 minutes to allow drying is the recommended first step.
Can I fix the E-45 error myself without calling a technician?
In many cases, yes. Start by opening the microwave door for 5 minutes to allow any moisture on the humidity sensor to evaporate, then close the door and try running a cooking cycle again. If the error clears and does not return, no further action is needed. If it persists after drying, further diagnosis of the sensor, wiring, or control board is required, which may need a qualified technician.
Will resetting the microwave clear the E-45 error?
A simple power reset alone may not permanently resolve E-45 if the underlying cause, such as moisture on the sensor, has not been addressed. The correct reset procedure is to open the microwave door for approximately 5 minutes to dry the sensor area, then attempt to restart the cooking cycle. If the root cause is a failed sensor or wiring fault, the error will return regardless of resets.
Is it safe to use my LG microwave while it is showing E-45?
When the E-45 error is active, the microwave interrupts the cooking process and should not be operated normally until the fault is resolved. Continuing to attempt cooking with a sensor fault present is not recommended, as the appliance cannot accurately monitor internal conditions. Address the error by following the drying procedure first before resuming use.
How much does it cost to repair an E-45 error on an LG microwave?
If the error is caused only by moisture on the sensor, there is no repair cost since drying the unit resolves the issue. If the humidity sensor itself has failed, parts and labor costs typically range from $75 to $200 depending on the specific model and local labor rates. A control board replacement, if required, is generally the most expensive outcome and can range from $150 to $350 or more including labor.

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