General Information

Component Location





General Description

The Engine Coolant Temperature (ECT) Sensor measures the temperature of engine coolant. The Engine Coolant Temperature (ECT) Sensor is located near the thermostat housing of the cylinder head. ECT Sensor is a thermistor (A Variable Resistor that Changes Along with ECT) in series with a fixed resistor in the Engine Control Module (PCM). The PCM applies 5 volts to the ECT sensor. The PCM monitors the voltage across the ECT sensor and converts it into a temperature reading. When the engine is cold the ECT sensor resistance is high, and when the engine is warm the ECT sensor resistance is low. Therefore, when the engine is cold the PCM will receive a high voltage input, and when the engine is warm the PCM will receive a low voltage input. The signal from ECT sensor is used for Injection, ignition timing, idle speed and cooling fan control.

DTC Description

The Engine Coolant Temperature High Rationality Diagnostic checks for unusually high engine coolant temperatures under normal operating loads.
PCM monitors difference between the start up and current coolant temperature and compares against the threshold while enable condition is met. If the PCM detects that the coolant temperature exceeds the limit under normal operating condition, PCM determines that a fault exists and a DTC is stored.

DTC Detecting Condition





Specification





Signal Waveform





Schematic Diagram