LG Dishwasher PE Error — Water Pressure Sensor Fix

What Does This Error Mean?

PE is the water pressure sensor — the device that monitors water level inside the tub during fill and drain.
If it reads out of range, the dishwasher can't safely manage water levels.
First check that the supply valve is fully open and the inlet hose isn't kinked.
If those are fine, the sensor or its tubing has failed and needs service-tech repair.

Affected Models

LG TrueSteam
LG QuadWash
LG LDF series
LG LDP series
LG smart dishwasher

Common Causes

Water supply partly closed (low pressure trips PE)
Inlet hose kinked or pinched
Sensor pressure tubing clogged with debris
Sensor itself failed
Controller's sensor input damaged

How to Fix It

Check the supply valve under the sink.

Find the small valve where the dishwasher's water line connects.
Should be fully open (handle parallel to the pipe).
If partly closed, that's your PE — open fully and try again.
Test water pressure at the sink.

Turn on the hot water at the kitchen sink.
Strong, steady stream?
If it's weak, the issue is house-wide.
Whole-house low pressure makes the dishwasher fill slowly enough to trigger PE.
Address the supply issue first.
Inspect the supply hose.

Trace the hose from under the sink to the back of the dishwasher.
Look for kinks where stored items have shifted into it.
Common in cabinets where things are squeezed in.
Straighten kinks and try again.
Clean the inlet filter.

Disconnect the supply hose at the dishwasher (turn off supply first).
Look at the inlet — there's a small mesh filter.
Clean any sediment under running water with a brush.
Reattach the hose.
Schedule service if PE persists.

If supply, hose, and filter are all good, the pressure sensor or its tubing has failed.
That's a service-tech fix — 100–200 USD parts plus labor.
Don't try to access the sensor yourself; it's behind panels with electronics nearby.

Frequently Asked Questions

Can a low water pressure house cause repeat PE?

Yes — if your house has marginal water pressure (under 30 PSI typical), the dishwasher fills slowly enough that PE may trigger occasionally.
A booster pump or a different inlet connection (closer to main supply) can help.
Discuss with a plumber if PE is a recurring annoyance.

Why doesn't PE clear after restoring full supply?

Some PE events latch — the controller stops trusting the sensor after one bad read.
Power-cycle the dishwasher (unplug or breaker for 5 minutes).
Restore power.
This forces a fresh sensor reading and clears the latched PE.
If PE returns, the cause is real.