LG Refrigerator Error Code Fridge 2nd Digit b

This code indicates a fault in the refrigerator compartment temperature sensor circuit. The main PCB has detected that the sensor signal at connector CN30 pins 3 and 6 is outside the valid 4.5V to 1.0V range, or that the sensor is reporting a temperature at or beyond +50°C or -50°C. Possible causes include a disconnected connector, a broken wire, a short circuit, or a failed thermistor. The refrigerator may not cool properly while this fault is active.

A reset may temporarily clear the error code from the display, but the code will return if the underlying sensor circuit fault is not corrected. The main PCB will continue to monitor the sensor signal and re-trigger the error any time the voltage remains outside the 4.5V to 1.0V range or the reported temperature stays beyond the valid limits. Diagnosis and repair of the sensor, wiring, or connector is required for a permanent fix.

Repair costs depend on which component is at fault. If the fix is simply reseating a loose connector, there may be no parts cost at all. Replacing a failed thermistor typically involves a relatively modest parts cost, while replacing the main PCB is the most expensive outcome. Including labor, total repair costs can range from around $75 to $350 or more depending on the fault and your location.

Start by checking the wiring connector at main PCB CN30 and at the sensor itself to make sure both are fully seated. Then measure the voltage between CN30 pins 3 and 6 with a multimeter; the reading should be between 1.0V and 4.5V. If the voltage is out of range, inspect the harness for damage such as cuts or pinched wires. If the wiring is intact and the connector is secure, the thermistor itself likely needs to be replaced.

Continuing to run the refrigerator with this error is not recommended, as the control board cannot accurately monitor the compartment temperature while the sensor fault is present. This means the fridge may not maintain safe food storage temperatures. Perishable food should be checked and the issue should be diagnosed and repaired as soon as reasonably possible.