NO.18 COOLING SYSTEM CONCERNS-RUNS COLD[AJ (3.0L Duratec)]

id0103a7802400

18
Cooling system concerns—runs cold
DESCRIPTION
•  Engine takes excessive period for reaching normal operating temperature.
POSSIBLE CAUSE
•  Thermostat malfunction
•  Condenser fan system malfunction
•  Cooling fan system malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
•  Is the customer complaint “Lack of passenger compartment heat” only?
Yes
Inspect the A/C and heater systems.
No
Go to the next step.
2
•  Does the engine speed continue at fast idle?
Yes
Go to symptom troubleshooting “No.9 Fast idle/runs on”.
No
Go to the next step.
3
•  Remove the thermostat and inspect operation.
•  Is the thermostat normal?
Yes
Access the ECT PID on M-MDS.
Inspect the both ECT PID and temperature gauge on instrument cluster readings.
•  If the temperature gauge on instrument cluster indicates normal range but ECT PID is not same as temperature gauge reading, inspect ECT sensor.
•  If the temperature gauge on instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
No
Replace the thermostat.
4
•  Verify the test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect related Service Information and perform repair or diagnosis.
•  If vehicle is repaired, troubleshooting completed.
•  If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.