LG Range Error Code E-28

The E-28 error code on an LG range indicates that the oven temperature sensor has developed a shorted circuit condition. Specifically, the sensor resistance has dropped below 100 ohms, which is far outside the normal operating range. The oven temperature sensor is a negative temperature coefficient (NTC) resistor that changes resistance in a predictable way as oven temperature changes. At room temperature, the correct resistance reading should be approximately 1080 ohms. When the sensor shorts internally or through its wiring harness, resistance collapses dramatically, and the oven control board receives an inaccurate temperature signal that it cannot interpret as valid.

This fault is distinct from an open circuit failure. A shorted sensor means current is finding an unintended low-resistance path rather than flowing correctly through the sensor element. Common causes include physical damage to the sensor probe itself, insulation breakdown on the sensor wiring from prolonged heat exposure, or a pinched wire that has allowed conductors to contact each other or a metal surface. In some cases, moisture or grease contamination inside the sensor connector can create a low-resistance bridge between the signal wires.

Diagnosing E-28 requires disconnecting power to the range and accessing the sensor by removing the upper rear cover panel. With power disconnected, measure resistance across the sensor leads. A healthy sensor reads around 1080 ohms at room temperature. Any reading well below 100 ohms confirms the shorted condition. Inspect the wiring harness along its full length before concluding the sensor itself is the failed component, as a wiring fault can produce the same low-resistance reading.