DTC 14, ECT Sensor High Temperature Indicated (With M/T): Notes

The Engine Coolant Temperature (ECT) sensor uses a thermistor to control signal voltage from ECM. The ECM applies and monitors voltage over circuit No. 410 to sensor. When engine is cold, sensor resistance is high. The ECM will sense a high signal voltage. As engine warms, sensor resistance becomes less and voltage drops. At normal engine operating temperature, voltage will be 1.5-2.0 volts.

1. DTC 14 will set if signal voltage indicates a coolant temperature greater than 275°F (135°C) for 3 minutes.
2. This test simulates conditions for DTC 15 to set. If ECM recognizes the open circuit (high voltage) and displays a low temperature, the ECM and wiring are okay.