An LG WashTower is not a washer-dryer combo and not a stacked pair. It is a single cabinet with a full-size washer below, a full-size dryer above, and one control panel mounted at the seam between them. That arrangement is comfortable to use and unusual to diagnose, because the panel is where every symptom shows up regardless of where it started. LG publishes a dedicated WashTower code guide precisely because the display speaks for two machines.
Read Which Side of the Panel Is Talking
The centre panel is divided: the washer controls and display occupy one side, the dryer controls and display the other, and each machine reports its codes on its own side. That division is your first clue. A code on the washer side is a washer code and belongs in LG's washer list; a code on the dryer side belongs in the dryer list. The same letters can appear on both sides with different meanings. dE on the washer side means the washer door; dE on the dryer side means the dryer door. tE on the washer side is the wash water thermistor; tE1 through tE4 on the dryer side are the dryer's thermistors. Write down the side as well as the code.
Washer-Side Symptoms
The lower machine is a front-load washer and behaves like one. IE means it did not fill in time: check both supply taps are fully open and the inlet screens are not blocked, with the taps closed while you unscrew a hose. OE means it did not drain: the drain pump filter sits low on the front of the cabinet behind a small door, and it is cleaned only with the WashTower disconnected from power and after the water has been let out through the small drain hose into a shallow pan. UE is an unbalanced load. A washer-side symptom with no code, such as a drum that fills but never turns, is still a washer fault.
Dryer-Side Symptoms
The upper machine is a standard LG dryer in a different cabinet. d90 and d95 are the Flow Sense warnings that the exhaust duct is restricted; nP on an electric model means one leg of the 240-volt supply is missing, and it is checked at the breaker panel, where one half of a double-pole breaker can trip while the handle looks normal. A dryer that tumbles without heat, or that runs long, is a dryer question even though the washer below shares its panel.
When the Shared Control Is the Fault
Some symptoms cannot be assigned to either machine, and those are the ones that point at the shared panel or its wiring. A display that is dark on both sides at once. Buttons on one side that operate the other side. Both machines refusing to start after a power interruption when neither shows a code. A panel that responds to touch on one half only, with the other half of the glass dead. In those cases the diagnosis is the control assembly and the harnesses that run through the cabinet to both machines, and that is technician territory.
Power and Access
How the two machines are supplied and how their cords are routed is laid out in the installation instructions for your model, and the safe way to remove power from the whole tower for any owner check is at the breaker for the laundry circuit rather than by reaching behind a cabinet that stands taller than you do. Do not pull the WashTower forward or tilt it to look behind it. It is heavy, top-heavy, and connected by hoses and a vent duct that are cut to length. Anything that needs the cabinet moved needs two people and belongs to the visit.
What to Tell Us
Report the side of the panel, the exact code, whether the other machine still runs normally, and whether the whole panel has ever gone dark. That set of facts usually settles the three-way question before anyone arrives, and it decides whether the visit is for a pump, a thermistor or a control. Book an LG WashTower repair with the model number from the plate inside the washer door.