Coolant Temperature Sensor/Switch (For Computer): Description and Operation

Location

Sensor threaded into thermostat housing.

Purpose

The The Control Module uses ECT sensor input to calculate injector pulse width, idle speed, and ignition spark advance, and lower boost level.

Operation

PCM provides sensor reference voltage of approximately five (5) volts.
Sensor maintains constant contact with engine coolant.

As coolant temperature changes, internal resistance of sensor changes, resulting in varying voltage drop across sensor.

Coolant And Charge Temperature Sensors:

Note:

The charge temperature sensor and coolant sensor are not interchangeable.

However, due to similarities in, appearance, connector type and thread, it is possible to install one in place of the other.

Interchanging these sensors can cause rough running, lack of power, an extremely rich air/fuel ratio, or a no start condition, (plugs will be fuel fouled).