MODEL PROFILE
Signal or code
Error codes and display signals
The official manual linked for this model documents these messages. Some indicators apply only to variants that display them; each entry is labeled as a code, indicator, or status.
No matching signal for this model.
Model and error-code facts may be shown in the language of the original source.
MODEL OVERVIEW
About this model: LG SDNTH981S
LG SDNTH981S: exact SIGNATURE dishwasher codes, CycleTrack and drying guidance.
Identify the Signature model before reading a code
SDNTH981S is the stainless member of LG's SDNTH981 family, not a generic dishwasher with the same two-letter fault display. The official owner booklet names SDNTH981* on its cover, while the separate LG specification prints SDNTH981S and its own UPC. That specification describes a 24-inch SIGNATURE machine with sixteen place settings, a stainless tub, an Iconic handle and a 39 dB sound rating. Its FlushFit cabinet profile and back-panel lighting are useful visual checks when a household has more than one LG appliance. The family cover makes the operating instructions applicable; the exact spec resolves the sales suffix. Record both identifiers before comparing an online code explanation with the panel in front of you.
Two displays serve different purposes
The hidden top controls appear after POWER is touched. Their numeric display ordinarily reports an estimated wash duration, remaining time or Delay Start hours. At the base of the door, CycleTrack projects remaining time onto the floor during a running cycle; the manual says a hazard icon appears there when an error occurs. A poorly visible projection on some flooring is specifically anticipated, so the top-panel message remains the better record of the exact characters. The flashing Rinse Aid light means refill is needed, and the Tub Clean reminder flashes every thirty cycles. Those maintenance lights should not be filed as a motor or leak failure. Photograph the full panel and note whether the floor icon was present before turning power off.
Separate water supply, drainage and leakage
The owner table puts IE with water inlet trouble and OE with drainage trouble. For IE it directs checks of the water supply and an inlet hose that may be clogged, kinked or frozen. For OE it points to the drain hose, air gap or disposal, and filters; these are separate flow paths and should not be treated as one interchangeable fault. AE is the leakage message. Its instruction is more urgent: turn off the dishwasher's water supply and contact LG. The manual explains that an AE event sounds an alert and intermittently runs the drain pump, even powering back on until the condition is resolved. FE means excessive water supplied and also directs the owner to LG support. A persistent AE or FE should not be hidden by repeated resets.
Read foam and heating warnings literally
The lower-case bE entry does not mean a communication failure. LG associates it with oversudsing from an unsuitable detergent, including ordinary hand dishwashing liquid, and also lists poor leveling. The manual even cautions that foamy food on dishes can trigger the warning. Use only detergent intended for an automatic dishwasher and check that the unit is level; follow the published cleaning procedure if residue remains. HE, by contrast, is a heater-circuit failure, and tE is a water-temperature-sensor error. The table does not provide a safe user repair for either component condition, so the article points to LG service rather than suggesting an internal electrical test. The same distinction keeps a simple detergent mistake from being confused with a heating fault.
Drying and drive codes match this model's equipment
This SIGNATURE dishwasher has Dynamic Heat Dry together with AutoVent Dry, and its official spec identifies a dedicated bottle-wash zone. Its manual therefore has meaningful entries for F35, a heated-air temperature sensor error, and F31, a heat-air-dry fan motor error. F37 refers to the Auto Open Dry motor rather than the water inlet. LE names the wash motor, while NE names the Vario motor. These five entries ask the owner to contact LG; they are not invitations to bypass a fan, latch or motor. If the dishes are merely wetter than expected without one of these messages, first check the selected dry option and rinse-aid setting instead of inventing a fault code.
Cycle labels are not fault labels
The panel offers Auto for sensed soil, Normal for routine loads, Heavy for baked-on residue, a one-hour wash and dry cycle for lightly soiled dishes, and a Downloaded position. The manual lists specialty downloaded cycles from Tub Clean through Dry Only; only one downloaded cycle is stored at a time, and Dry Only requires a feature update before use. P1 through P10 on the panel identify these selections, not failures. CL means Control Lock, and L0 through L4 belong to rinse-aid adjustment; test-mode strings beginning with N, U, d or t are likewise described as nonerror states. A cycle choice photographed without context can look like a diagnostic. Keep the message's letters, timing and selected program together.
Installation facts explain some first-run symptoms
LG specifies 20 to 80 psi supply pressure and 120 to 149 degrees Fahrenheit inlet water for the SDNTH981* family. Its installation check asks for a smooth door closure, an opened house supply, and a cycle observed for leaks at both supply and drain connections. The installation code chart gives OE for a kinked or pinched drain route, a disposal knockout left in place, or a clogged waste connection; IE can follow a kinked supply line or a closed faucet. That makes a code immediately after fitting the appliance different evidence from a code after months of use. The separate spec recommends a standard opening and no more than twelve feet between dishwasher and sink for proper drainage.
Use the model's service and maintenance path
The premium rack layout is more than a capacity headline: the specification lists a three-level adjustable upper rack, a premium third rack, four spray arms and a BlastZone bottle wash area. Loading a tall item under the upper arm or crowding the bottle area can affect washing without producing any error message. For routine care, the manual describes cleaning the filters and spray arms, while the ThinQ app can report appliance status and offer Smart Diagnosis. Those aids do not replace the local code table. Keep the owner's PDF, exact SKU, date, photographed display and any recent installation or detergent change together when contacting LG. This gives support the relevant conditions without assuming the failed part from a two-character code alone.
Verified model details
Exact official LG owner and specification
Source for this detail · Source page: 1Twelve genuine displayed error messages
Source for this detail · Source page: 8Cycle and maintenance states separated from faults
Source for this detail · Source page: 54
This description summarizes the linked source documents; check each cited source for your exact model and region.
Manufacturer source
Open official source
LG SIGNATURE FlushFit™ Dishwasher w/ QuadWash® Pro - SDNTH981S | LG USA
Open official sourceIf there is a safety risk, stop using the appliance and follow the manufacturer’s instructions.