Kenmore Refrigerator Error Code Er 4

The Er 4 error code on a Kenmore refrigerator indicates an abnormal condition detected on the secondary refrigerator temperature sensor, sometimes referred to as the middle room sensor. This sensor is responsible for monitoring temperatures in a secondary zone within the refrigerator compartment, and the control board uses its readings to regulate cooling cycles accurately. When the board detects a signal that falls outside the expected resistance range, either due to an open circuit (cut wire) or a short circuit, it logs Er 4 and may alter or suspend normal operation to protect food and components.

The first recommended diagnostic step is to inspect the connector designated CON7, which carries the signal from this sensor to the control board. Loose, corroded, or improperly seated connector pins are a frequent source of intermittent or permanent signal loss and can mimic a failed sensor. After confirming a secure connection at CON7, the sensor itself should be tested with a multimeter to verify its resistance output matches the expected value at a known temperature. A cut wire in the sensor harness will produce an open circuit reading, while a shorted wire or failed sensor will show near-zero resistance.

If the wiring harness and connector check out, the sensor itself is likely defective and will need replacement. In some cases, the control board may fail to correctly interpret a valid sensor signal, though this is a less common cause. Addressing this fault promptly is worthwhile because inaccurate temperature monitoring can lead to inconsistent cooling and potential food spoilage.