Engine - Coolant Temperature Sensor/Switch: Description and Operation

PURPOSE
Provide PCME with engine coolant temperature signal.

LOCATION
Front of intake manifold.

OPERATION
Sensor is a thermistor with a negative temperature coefficient; as temperature increases, resistance decreases. PCME measures resistance changes and calculates engine temperature. PCME monitors engine coolant temperature to calculate injector pulse width during cold start and warm-up, and to regulate other output functions.

TEMP. RESISTANCE (K OHMS)

-20°C (-4°F) 14.6 - 17.8
20°C (68°F) 2.2 - 2.7
40°C (104°F) 1.0 - 1.3
60°C (140°F) 0.50 - 0.65
80°C (176°F) 0.29 - 0.35