Note. For circuit reference (Схема №4)
Circuit Description
Engine Coolant Temperature (ECT) sensor is a thermistor or a variable resistor, that varies resistance based on temperature. As temperature of ECT sensor increases, resistance decreases. High temperature will result in a low signal voltage. ECT sensor value will be about 1.5-2.0 volts when the engine is fully warmed.
Conditions required to set DTC are
- Engine running time greater than 2 minutes.
- ECT sensor signal indicates -38°F (-37°C), about 5 volts, for 12 seconds over a 25-second period.
Diagnostic Aids
Check for faulty connections or damaged harness. Ensure harness is not routed too close to high voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See ECT SENSOR RESISTANCE VALUES .