Test Procedure

K1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Are DTCs P0115, P0116, P0117, P0118, P0128, or P1116 present?

Yes	No
GO to K2.	RETURN to SYMPTOM CHARTS for further direction.

K2 CHECK THE ENGINE COOLANT LEVEL

WARNING: ALWAYS ALLOW THE ENGINE TO COOL BEFORE OPENING THE COOLING SYSTEM. DO NOT UNSCREW THE COOLANT PRESSURE RELIEF CAP WHEN THE ENGINE IS OPERATING OR THE COOLING SYSTEM IS HOT. THE COOLING SYSTEM IS UNDER PRESSURE; STEAM AND HOT LIQUID CAN COME OUT FORCEFULLY WHEN THE CAP IS LOOSENED SLIGHTLY. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN SERIOUS PERSONAL INJURY.

Check the engine coolant and the secondary cooling system levels.

Is the coolant fill level correct?

Yes	No
GO to K3.	REFER to the appropriate Engine Cooling, Diagnosis and Testing article to continue diagnosis. Clear the PCM DTCs. REPEAT the self-test.

K3 CHECK THE RESISTANCE OF THE ECT OR THE SENSOR WITH THE ENGINE OFF

NOTE: Verify the engine temperature is at ambient room temperature before continuing with this test. A soak period of 8 hours may be required. Refer to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS for information concerning DTC P0115, P0116, or P1116.

NOTE: Refer to the chart at the beginning of this test for the resistance specifications.

ECT Sensor connector disconnected.
Measure the resistance between:

(+) ECT Sensor Connector, Component Side	(-) ECT Sensor Connector, Component Side
ECT	SIGRTN

Is the resistance within specification?

Yes	No
GO to K4.	INSTALL a new ECT sensor. REFER to the appropriate Electronic Engine Controls article. Clear the PCM DTCs. REPEAT the self-test.

K4 CHECK FOR AN OPEN

Ignition OFF.
PCM-E connector disconnected.
Measure the resistance between:

(+) PCM-E Connector, Harness Side	(-) ECT Sensor Connector, Harness Side
ECT	ECT
SIGRTN	SIGRTN

Is the resistance less then 5 ohms?

Yes	No
GO to K5.	REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

K5 CHECK FOR A SHORT TO GROUND

Measure the resistance between:

(+) ECT Sensor Connector, Harness Side	(-)
ECT	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to K6.	REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

K6 CHECK THE SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

Ignition ON, engine OFF.
Measure the voltage between:

(+) ECT Sensor Connector, Harness Side	(-)
ECT	Ground

Is any voltage present?

Yes	No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.	GO to K7.

K7 CHECK THE RESISTANCE OF THE ECT SENSOR

NOTE: Refer to the chart at the beginning of this test for the resistance specifications.

NOTE: Verify the engine is at operating temperature before taking the ECT reading.

ECT Sensor connector connected.
Run the engine until the engine temperature stabilizes.
Ignition OFF.
ECT Sensor connector disconnected.
Measure the resistance between:

(+) ECT Sensor Connector, Component Side	(-) ECT Sensor Connector, Component Side
ECT	SIGRTN

Is the resistance within specification?

Yes	No
For DTCs P0116 and P0128, GO to K8. For all others, The system is operating correctly at this time. RETURN to SYMPTOM CHARTS for further direction.	INSTALL a new ECT sensor. REFER to the appropriate Electronic Engine Controls article. Clear the PCM DTCs. REPEAT the self-test.

K8 CHECK THE SENSOR OPERATION

Run the engine until the engine temperature stabilizes.
Verify the radiator hoses are hot and the cooling system is pressurized.
For F-650/F-750,
Access the PCM and monitor the ECT (TEMP) PID.
For all others,
Access the PCM and monitor the ECT1 (TEMP) PID.

Is the temperature greater than 77°C (170.6°F)?

Yes	No
The test is complete. DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS .	REFER to the appropriate Engine Cooling article to diagnose why the engine does not reach operating temperature. REPAIR as necessary. Clear the PCM DTCs. REPEAT the self-test.