Fridge
ER RT
The ER RT error code on an LG fridge signals a fault with the room temperature sensor (also called the ambient sensor), which the appliance uses to adjust cooling based on your kitchen’s temperature. It’s not an immediate emergency, but ignoring it can lead to inefficient cooling and higher energy bills.
What does this error mean?
LG fridges use a room temperature sensor to monitor the ambient environment around the appliance. When the fridge detects that this sensor is sending no signal, an out-of-range reading, or a short circuit, it throws the ER RT code. The fridge may still cool to some degree, but it can no longer optimise its compressor cycles correctly, meaning food safety could be compromised over time.
Est. repair cost
£15–£35 DIY sensor part; £80–£150 for professional sensor repair; £150–£250 if the main PCB needs replacing
🔍 Likely causes
🛠️ Step-by-step fix
Reset the fridge: Unplug it from the mains, wait 10 minutes, then plug it back in. If the error clears and doesn’t return within 24 hours, it was likely a temporary glitch.
Check the door and vents aren’t obstructed: Ensure the fridge has at least 5cm clearance on all sides so the ambient sensor can get an accurate room temperature reading.
Locate the room temperature sensor: On most LG fridges it sits near the top of the unit, often behind the control panel or near the door frame. Consult your model’s user manual or the LG UK support site for the exact location.
Inspect the sensor and its wiring: With the fridge unplugged, check for any visible damage to the sensor body, and ensure the wiring connector is firmly seated. If a connector is loose, press it firmly back into place and test.
Test the sensor with a multimeter (if confident): A functioning NTC room temperature sensor should read approximately 5–10 kΩ at 25°C. A reading of zero or infinite resistance confirms the sensor has failed and needs replacing.
Replace the room temperature sensor: Genuine LG replacement sensors are available from LG UK parts suppliers or reputable UK appliance parts retailers. Disconnect the old sensor, connect the new one, and restore power to test. If the error persists after sensor replacement, the control board is likely faulty — stop here and call a professional.
📞 When to call a professional
Call a professional if the error code returns after a reset and sensor replacement, or if you are not comfortable using a multimeter or handling internal fridge components. Tell the engineer you have an ER RT fault code, that you suspect the room temperature sensor or main PCB, and the full model number (found on the label inside the fridge door). An experienced appliance technician should be able to diagnose and resolve this within a single visit.
⚖️ Repair or replace?
A room temperature sensor replacement typically costs £80–£150 through a UK appliance repair engineer, including parts and labour. If the fault lies with the main control board, expect £150–£250. For any LG fridge under 8 years old in otherwise good condition, repair is almost always the better value. If your fridge is over 10 years old and the control board is at fault, replacing the appliance may be more cost-effective than investing in an expensive repair.