Coolant Pump, Thermostat and Cable. Radiator and Connections.
Engine Coolant Temperature Sensor.

TEMPERATURE SENSOR

Engine Coolant Temperature Sensor
If your engine coolant temperature sensor has failed, you may notice one of several symptoms: your temperature gauge doesn’t move, your engine overheats without warning, your radiator fans don’t switch on, or they don’t switch off. If your 2019 Volvo XC40 has any of these symptoms, it's a good idea to let a trained Volvo technician perform an inspection.