The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. The ECM monitors the performance of the ECT sensor. If the ECM detects excessive noise or rapid fluctuations in the ECT signal, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage:

DTC P0119 is a Type B DTC.

DTC P0119 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. Observe the engine coolant temperature (ECT) sensor parameter with a scan tool while moving the ECT sensor connector and the engine control module (ECM) connector. The ECT sensor parameter should not fluctuate while moving the related harnesses and connectors.

⇒	Repair the suspected harness or connection if the ECT parameter fluctuates more than 3°C (5°F) while moving the related harnesses and connectors.

2. Inspect the engine coolant level. Verify that the cooling system is operating correctly.

⇒	If you suspect a condition with engine cooling system, refer to Symptoms - Engine Cooling .

3. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. DTC P0119 should not set.

1. Ignition OFF, disconnect the engine coolant temperature (ECT) sensor.
2. Ignition ON, verify that the scan tool ECT sensor parameter is at -40°C (-40°F).

⇒	If greater than the specified value, test the signal circuit of the ECT sensor for a short to ground. If the circuit tests normal, replace the engine control module (ECM).

Notice: Do NOT use a test lamp to test the continuity of the circuit. Damage to the control module may occur due to excessive current draw.

Important: The control module or the sensor may be damaged if the circuit is shorted to B+.

3. Test for less than 1 volt between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified value, test the low reference circuit for a short to B+. If the circuit tests normal, replace the ECM.

4. Ignition OFF, remove the fuse that supplies B+ to circuit terminal C2-56 of the ECM.
5. Test for less than 5 ohms between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

6. Install the fuse that supplies B+ to circuit terminal C2-56 of the ECM.

Important: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

7. Ignition ON, install a 3A fused jumper wire between the signal circuit and the low reference circuit and verify the scan tool ECT sensor parameter is greater than 142°C (288°F).

⇒	If less than the specified value, test the signal circuit of the ECT sensor for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

8. If all circuits test normal, test or replace the ECT sensor.

1. Ignition OFF, disconnect the harness connector of the intake air temperature (ECT) sensor.

Important: A thermometer can be used to test the sensor off the vehicle.

2. Test the ECT sensor by varying the sensor temperature while monitoring the sensor resistance. Compare the readings with the Temperature Versus Resistance - Engine Coolant Temperature Sensor table and verify that the resistance is within 5 percent of the specification.

⇒	If not within the specified range, replace the ECT sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.