LG Refrigerator Error Code Communication error

This error code indicates a communication failure between the main MICOM (microcontroller) and the linear drive MICOM, which is the dedicated controller for the linear compressor. These two control boards exchange data signals continuously during normal operation. When that signal path breaks down, the refrigerator responds by shutting off the compressor and closing the damper to prevent uncontrolled operation in a degraded state.

The primary diagnostic entry point is checking the voltage at IC1 PIN60 on the main board and IC201 PIN18 on the linear drive board. During healthy communication, both pins will show a fluctuating voltage in the 1 to 4 volt range, reflecting the active data signal passing between the two controllers. If either pin reads a steady 0V or a fixed 5V with no fluctuation, that indicates the communication line is dead. A stuck-low reading (0V) often points to a short or a failed output stage, while a stuck-high reading (5V) can indicate an open circuit or a failed pull-down on the receiving end.

Common root causes include damaged wiring harnesses between the two boards, corroded or loose connectors at either MICOM, moisture intrusion on the board causing trace damage, or outright failure of one of the two control boards. Because the compressor shuts off when this error is active, the refrigerator will lose cooling capacity quickly. Systematic voltage testing at the specified pins is the fastest way to isolate whether the fault is in the wiring path or in one of the two control boards themselves.