PE refers to an anomaly in water level detection on documented LG front-loaders. The message is not enough to determine that the sensor needs to be replaced.
LG identifies it in its front-load error chart. Level reading depends on a system; the visible code does not separately verify the sensor, wiring, or circuit.
What information you can gather
Note whether PE appears as soon as you turn it on, after it starts filling, or while draining. Observe from the outside whether there is water left behind or whether the level is rising. That information helps pinpoint the issue, but it does not replace a technical measurement.
If there is overfilling, shut off the water supply and stop using it. If there is no leak or other sign of damage, check whether your manual allows an electrical reset and follow only that instruction. When PE returns, repeating it does not add a useful check.
Do not blow into hoses, disconnect connectors, or access the sensor under the cover. Intervening in the level circuit can affect fill safeguards. FE for overfilling and IE for insufficient filling describe other signals and should only be consulted if they match what is shown.
Give service the washer model and the stage at which PE appears so they can check the complete level system.