DTC 14

DTC 14 Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION:

The Engine Coolant Temperature (ECT) Sensor uses a thermistor to control the signal voltage to the ECM. The ECM applies a voltage on circuit 410 to the sensor. When the engine is cold the sensor (thermistor) resistance is high, therefore the ECM will see high signal voltage. As the engine warms, the sensor resistance becomes less, and the voltage drops. At normal engine operating temperature 85°C to 95°C (185°F to 203°F) the voltage will measure about 1.5 to 2.0 volts.


TEST DESCRIPTION: The numbers below refer to circled numbers on the diagnostic chart.

1. A DTC 14 will set if:
^ Signal voltage indicates a coolant temperature above 135°C (275°F) for two seconds. (4.3L)
^ Signal voltage indicates a coolant temperature above 150°C (302°F) for two seconds. (5.0L & 5.7L)

2. This test will determine if circuit 410 is shorted to ground which will cause the conditions for a DTC 14.


DIAGNOSTIC AIDS:

^ Check harness routing for a potential short to ground in circuit 410.

^ Check terminals at sensor for good contact.

^ A "Scan" tool displays engine temperature in degrees centigrade and fahrenheit. After the engine is started, the temperature should rise steadily to about 90°C (194°F) then stabilize when thermostat opens.