ECT

📖 YOUCANIC Automotive Glossary

The ECT (Engine Coolant Temperature) sensor measures coolant temperature for cold-start enrichment, idle speed control, fan activation, and closed-loop timing. An NTC thermistor reading ~4.0V cold to ~0.5V hot. A sensor stuck cold keeps the ECU in open-loop enrichment (rich, poor economy); stuck hot causes lean cold-starts and fans running unnecessarily. DTCs: P0115-P0119, P0128.

Compare live data to an infrared thermometer on the thermostat housing to verify accuracy.