Tony's A Turlock , CA June 19, 2016 Appliance: LG Refrigerator LSC27931SB Lg Side-By-Side Refrigerator Lsc27931sb: Lf fridge showing code er ds defrost sensor. How to replace Refrigerator Temperature Sensor. Replaced defrost sensor which is the controller assembly and error code gone 1 People found this story helpful Do-It-Yourself Rating: Repair Time Estimate: 15-30 minutes