Rodeo (2WD) L4-2559cc 2.6L SOHC (4ZE1) (1991)
Engine Temperature Sensor: Description and Operation
Coolant Temperature Sensor
PURPOSE
Supplies the Engine Control Module (ECM) with engine temperature information.
LOCATION
Under the intake manifold at the front.
OPERATION
The ECM supplies a 5V signal to the sensor and measures voltage variation. By measuring this variation, the ECM measures coolant temperature.
This input is a factor in calculations involving most ECM controlled systems.
At 20°C (68°F), resistance of the sensor is between 2 - 3K ohms. When the engine is warm (80°C / 176°F), resistance falls to between 200 - 400
ohms.
CONSTRUCTION
The coolant temperature sensor is a thermistor (a device whose resistance changes with temperature). Being immersed in a coolant passage allows
the sensor to detect engine temperature.