Pinpoint Test AJ: Engine Coolant Temperature And Engine Oil Temperature Correlation : Introduction

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2005 Ford RV Cutaway, 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Excursion. However, it is still accessible from the selected car via links, so may be relevant.

WARNING: WARNING: STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS ARE MANDATORY WHEN CARRYING OUT THE ROAD TEST. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.

This pinpoint test is intended to diagnose the following:

low engine coolant level
cooling system flow restriction
ECT sensor
EOT sensor

AJ1 CHECK FOR AN ENGINE COOLANT LOSS OR AN ENGINE OVERHEATING CONCERN

Carry out a visual inspection. Refer to the appropriate Engine Cooling, Inspection and Verification article.
Verify the pressure relief cap is capable of holding system pressure.
Verify that the coolant and cooling system maintenance has been carried out as recommended.

Is the engine overheating or loosing coolant?

Yes	No
Refer to the appropriate Engine Cooling, Inspection and Verification article, to continue diagnosis of the engine overheats or the loss of coolant symptoms.	Go to AJ2.

AJ2 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Retrieve and record all DTCs.
Record the freeze frame data.

Are there any other DTCs present?

Yes	No
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. Go to ENGINE CONTROLS - DIAGNOSTIC SUBROUTINES -- 6.0L DIESEL article .	Go to AJ3.

AJ3 CHECK ECT OR EOT SENSOR FOR DAMAGE

Inspect the ECT and EOT sensor and circuits at the sensor and PCM for the following:

pinched, shorted, and corroded wiring and pins
oil or water contamination
crossed sensor wires
contaminated or damaged sensor

Is a concern present?

Yes	No
REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.	Go to AJ4.

AJ4 CHECK FOR CORRECT ECT AND EOT SENSOR OPERATION

NOTE: Verify that no accessories are in use (engine block or oil heaters).

Clear all the DTCs.
Cold soak the vehicle at ambient temperature for a minimum of 10 hours.
Ignition ON, engine OFF.
Access the PCM and monitor the ECT and EOT PIDs.
Access the PCM and monitor the RPM PID.
Access the PCM and monitor the MFDES PID.
Record the ECT and EOT sensor temperature values.
Drive the vehicle at an engine speed greater than 1,800 RPM and 15 mg/stroke MFDES for at least 15 minutes. Select the appropriate gear to achieve the operating conditions.

Does the ECT PID and EOT PID temperature values change by a minimum of 6°C (10°F) from when the ignition ON, engine OFF valves were recorded?

Yes	No
INSTALL a new oil cooler kit. REFER to the appropriate Engine, Oil Cooler article.	INSTALL a new ECT sensor or EOT sensor in question. CLEAR the DTCs. REPEAT the self-test.