Engine Coolant Temperature Sensor
The Engine Coolant Temperature (ECT) sensor is a 2-wire Negative Thermal Coefficient (NTC) sensor. ECT sensor protrudes into an engine water jacket. See Fig 1 -Fig 5 . As engine coolant temperatures increases, voltage decreases. When engine coolant temperature decreases, voltage increases. When ignition is on, PCM sends a regulated 5-volt signal to ECT sensor. When engine is cold, PCM operates in open loop. PCM will command richer air/fuel mixtures and higher idle speeds. When engine reaches operating temperature, PCM will use input from the ECT sensor for the following calculations.
- For Engine Coolant Temperature Gauge Operation Through CCD Or PCI (J1850) Communications
- ASD Relay Shutdown Times
- EVAP Purge Solenoid On/Off Times
- Fuel Injector Pulse Width
- Fuel Injector Pulse Width During Engine Cranking
- Idle Air Control Motor Key-On Steps
- Ignition Spark Advance Curve
- Leak Detection Pump Operation
- O2 Sensor Closed Loop Times
- Radiator Fan Relay On/Off Times (If Equipped)
- Target Idle Speed
The ECT sensor resistance values are the same as the Intake Air Temperature (IAT) sensor.