Frigidaire Cooktop Error Code E77

Error code E77 on a Frigidaire induction cooktop indicates a break or open-circuit condition in the heat sink temperature sensor for the center cooking zone within a 3-cook-zone induction module. The heat sink sensor is a thermistor that continuously monitors the temperature of the power electronics on the generator circuit board. This sensor protects the induction module from overheating by feeding real-time thermal data back to the control system. When the circuit is broken, the control board loses visibility into heat sink temperatures and shuts down the center zone as a protective measure.

The generator circuit board for the center zone houses the IGBT transistors and associated power components that drive the induction coil. The heat sink sensor is typically mounted directly on or near these components and is often integrated with or hardwired into the board assembly. A break in the sensor circuit can result from a physically damaged sensor, a failed solder joint on the board, a disconnected or corroded harness connector, or a thermistor that has gone open-circuit due to thermal stress over time.

Because the sensor circuit is closely tied to the generator board, and because tracing individual sensor failures on induction power boards can be impractical without specialized test equipment, the primary diagnostic step is to replace the generator circuit board for the center cook zone. This board swap addresses both a failed sensor and any underlying board-level fault that may have caused or contributed to the open-circuit condition.