As an expert technician, I have diagnosed the LG refrigerator with error code E CO. This specific code indicates a Communication Error between the Main Control Board (located at the back or top of the unit) and the Display Control Board (located on the door). Essentially, the two “brains” of the refrigerator are unable to send or receive data signals to one another.
LG refrigerator with error code E CO: Diagnostic and Troubleshooting Steps
- Perform a Hard Reset: Unplug the refrigerator from the wall outlet for exactly 10 minutes. This allows the capacitors on the Main Control Board to discharge and may clear a temporary software glitch.
- Inspect the Door Hinge Wiring: Open the refrigerator door and locate the plastic cover over the top hinge. Remove the screw and the cover. Inspect the wiring harness for any pinched, frayed, or broken wires. This is the most common failure point due to the constant movement of the door.
- Reseat Harness Connectors: Disconnect and reconnect the plastic wire harnesses at the top hinge and at the Main Control Board (located behind a metal panel on the rear of the fridge). Ensure you hear a “click” to confirm they are fully seated.
- Check for Moisture: Inspect the connectors for any signs of corrosion or moisture. If green or white crust is present, clean it with electrical contact cleaner.
- Test the Main Control Board: If the wiring is intact, the issue is likely a failed communication circuit on either the Main Control Board or the Display Control Board.
Expected Ohmic/Resistance Values
While communication signals are typically measured in DC voltage (usually 5V or 12V pulses), you can test the integrity of the components and sensors using a multimeter:
- Wiring Harness Continuity: 0.1 – 0.8 Ω (Any value over 1 Ω indicates a broken or damaged wire).
- Temperature Sensors (Thermistors): ~5k Ω to 10k Ω at room temperature (77°F).
- Evaporator Fan Motor: 1.5k Ω – 3.0k Ω between the red and white wires.
- Defrost Heater: 20 – 50 Ω.
Estimated Repair Cost
- Wiring Harness Repair: $10 – $30 USD (if DIY soldering/splicing).
- Display Control Board: $85 – $160 USD.
- Main Control Board: $130 – $260 USD.
Warning: Always disconnect the refrigerator from the power source before removing any covers or touching electrical components. Failure to do so can result in severe electric shock or permanent damage to the sensitive electronic boards. If you are testing live voltage, use extreme caution and insulated probes.
Repair Difficulty
Difficulty: Intermediate.
This repair is manageable for a DIYer comfortable with a multimeter and basic hand tools. However, if the wiring harness inside the door itself is severed, it may require a professional or a full door replacement, as those wires are often foamed into place and cannot be easily swapped.
I am a master Appliance Repair technician with over 35 years of experience in the field. I am passionate about helping people troubleshoot their appliances and fix common problems. My website, appliancemode.com, provides a wealth of information on troubleshooting common appliance issues and deciphering error codes. This website aims to empower people to tackle appliance repairs themselves and save money on service calls.
