The sensor is to maintain a certain distance from the vehicle in front. However, the smudged sensor lens with foreign substances, such as snow and rain, adversely affects the sensing performance. It may even temporarily cancel the AEB. Always keep the sensor lens clean.
Kia Niro 2017 (DE HEV) Service Manual: Engine Coolant Temperature Sensor (ECTS) Repair procedures
Inspection
1.
Switch "OFF" the ignition.
2.
Remove the ECTS (Refer to "Removal").
3.
After immersing the thermistor of the sensor into engine coolant, measure
resistance between the ECTS terminals ...
Kia Niro 2017 (DE HEV) Service Manual: Auto Defogging Sensor Repair procedures
Replacement
1.
Disconnect the negative (-) battery terminal.
2.
Remove the auto defogging sensor cover (A).
3.
Using a screwdriver or a remover, remove the LDWS & rain sensor cover
(A).
...