Disconnected wire of the temperature sensor.

Check if the wire (reference 7 image) of the temperature sensor is plugged into its socket on the Signal Backplane.

Damaged wire of the temperature sensor.

1. Repair the wire of the temperature sensor which measures the heat sink temperature of the green channel (reference 17 image) .

2. If not repairable, replace the temperature sensor.

Defect temperature sensor.

Replace the temperature sensor (reference 17 image) which measures the heat sink temperature of the green channel.