Engine - Coolant Temperature Sensor/Switch: Description and Operation

Location in cylinder head between cylinders 3 + 4






Location in cylinder head between cylinders 1 + 2





Design
Metal housing with an NTC resistor. 2-pin connector.
Connection assignment at connector:
Connections 1 and 2 engine control module

Task
Detecting the coolant temperature and supplying signal to the engine control module.

Operation
The NTC resistor integrated in the coolant temperature sensor (B11) alters its electrical resistance in line with the coolant temperature. NTC means negative temperature coefficient, i.e. the electrical resistance drops as the temperature rises

Example:
Coolant temperature Resistance
20 °C 3100 Ohms
80 °C 315 Ohms