LG Dishwasher tE: The Temperature Sensor Gives an Impossible Reading

tE means the NTC thermistor's resistance reading fell outside the physically possible range. The board expects a resistance that corresponds to a temperature between roughly 32 degrees F and 200 degrees F. If the reading is infinite (open circuit — sensor wire broken) or near zero (shorted — wires touching), no real-world temperature produces that value, so the board flags tE.

tE vs. HE: Different Problems, Related Systems

tE and HE both involve the heating system but report different failures. tE means the sensor circuit itself is broken — the board cannot read any temperature at all. HE means the board reads temperature fine but the value is not rising as expected (heater is not heating). With tE, the board does not know the water temperature and will not energize the heater at all (safety precaution — heating without temperature feedback risks overheating). With HE, the board reads a low temperature and tries to heat but cannot reach the target.

If the sensor wire is partially damaged (high resistance, not fully open), the board may read a plausible but wrong temperature. This produces HE rather than tE because the reading looks valid even though it is inaccurate. True tE requires a completely out-of-range reading.

Finding and Testing the Thermistor

The NTC thermistor in LG dishwashers is a small capsule or bead sensor mounted in the sump area where it contacts wash water. Its two thin leads run through the sump wall to a connector on the underside of the tub, then through a harness to the main board.

Thermistor Resistance Test

1. Breaker off
2. Locate the thermistor connector. On most LG models, it is accessible from below through the kick plate opening — look for a small 2-pin connector near the sump
3. Disconnect the connector. Measure resistance across the two thermistor pins at the sensor side (not the harness side)
4. At room temperature (68 degrees F): expect 5,000-6,500 ohms
5. Warm the sensor body with your hand for 30 seconds: resistance should drop noticeably (to approximately 3,500-4,500 ohms at body temperature)
6. Results:
   • Infinite (OL on meter) = open circuit in the sensor. Replace the thermistor
   • Near zero (under 100 ohms) = sensor is shorted. Replace
   • Correct range but does not change with temperature = sensor is stuck at one value. Replace
   • Correct range and changes with temperature = sensor is fine. Check the harness and board

Harness Continuity Test

If the thermistor itself passes, the break is in the wiring between the sensor and the board:

1. Leave the thermistor disconnected
2. At the main board, locate the thermistor input connector (refer to the tech sheet diagram)
3. Measure continuity from each harness pin at the sensor connector to the corresponding pin at the board connector
4. Both wires should show near-zero resistance. Infinite on either wire = broken wire in the harness

The most common harness failure point is where the wire passes through grommets or routing clips near the sump — moisture and heat degrade the insulation and corrode the copper inside.

Thermistor Replacement

The thermistor is inexpensive (EBG61106803, $8-15) and accessible:

1. Breaker off. Access from below through the kick plate
2. Disconnect the old thermistor's 2-pin connector
3. The thermistor body mounts into a socket in the sump wall — pull it straight out. Some models have a retaining clip
4. Push the new thermistor into the socket until it seats against the sump wall. The sensing end must contact wash water inside the sump
5. Route the new leads cleanly away from heat sources and sharp edges. Connect to the harness
6. Restore power and run a test cycle. tE should not return

Parts and Cost

Why the Dishwasher Stops Everything With tE

Without a valid temperature reading, the board cannot safely control the heater element. Running the heater without feedback risks overheating the water (potentially damaging plastic tub components or burning detergent residue onto dishes) or continuously heating past safe limits. The board takes the conservative approach: refuse to heat, refuse to run Sanitize or heated-dry cycles, and display tE.

Some LG models allow cold-water-only cycles (rinse, light wash) to continue with tE active. Others lock out all cycle starts. Check whether your dishwasher will run any cycle with tE — if it runs cold cycles normally, you can use it for light loads while waiting for the replacement sensor.

Common Misdiagnosis: tE Blamed on the Board

tE is overwhelmingly a sensor or wiring problem. The board's thermistor input is a simple resistive measurement circuit with almost no failure-prone components (no relays, no high-power transistors). Replacing the main board for tE without testing the thermistor and harness first wastes $120-200. Always test the $8 sensor before buying the $150 board.

NTC Sensor Drift Over Time

NTC thermistors are solid-state devices with a long life, but constant immersion in hot, chemically active wash water does affect them. After 8-10 years of daily use, the sensor material's resistance curve can drift — it still changes with temperature but no longer matches the board's lookup table. A 10% drift at operating temperature (120-150 degrees F) causes the board to read temperature 5-10 degrees off. This drift rarely causes tE (the reading is still in range) but does cause HE (the board thinks water is colder than it actually is). Replacing the thermistor prophylactically at the 8-10 year mark prevents both HE and eventual tE.

tE With Visible Water Damage

If you see water damage, corrosion, or mineral deposits on the thermistor connector or the nearby harness, clean everything thoroughly with electrical contact cleaner before replacing any parts. A corroded connector can create enough resistance to push the sensor reading out of range — cleaning the connector and re-seating it may resolve tE without any parts purchase.

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LG dishwasher flashing tE? The thermistor is a $8-15 sensor with a 10-minute replacement — we test before we replace. Book sensor diagnosis.