LG · Washing Machine
LG Washing Machine PE Error Code
Water level sensor fault
What this error means
PE indicates a Pressure Error—the water level sensor is not sending a valid signal to the main board. The washer may refuse to fill, drain, or advance cycles because it cannot determine how much water is in the tub.
How PE is detected
When PE appears on a LG washing machine, the control board has confirmed that water did not leave the machine within the programmed drain window. On LG WM3400CW, LG WM3700HWA, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most PE calls are resolved without parts: unplug the washer and locate the thin clear hose running from the tub to the top control housing. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If PE returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Air dome hose disconnected or cracked between tub and pressure switch
- Pressure switch diaphragm failed or clogged with detergent residue
- Loose wire connector at the pressure sensor on the control board
- Main control board pressure input circuit damaged
Step-by-step fixes
- 1Unplug the washer and locate the thin clear hose running from the tub to the top control housing
- 2Remove the hose at both ends and blow through it—air should pass freely with no blockage
- 3Reattach the hose firmly to the tub air dome nipple and pressure switch port
- 4Run a small load cycle and watch whether fill stops at the correct level
When to call a technician
If the hose is intact and PE returns, the pressure switch or control board input needs bench testing with a multimeter.
Affected models
- LG WM3400CW
- LG WM3700HWA
- LG WT7800CW
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use washing machines to prevent PE from lint and food debris buildup.
- Record when PE appears in the cycle and whether it clears after a 60-second power reset on your LG washing machine—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for PE; LG uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting PE; reversed plugs on pumps and valves cause immediate repeat faults.