NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [YF (2.0L Zetec)]


18	COOLING SYSTEM CONCERNS -RUNS COLD
DESCRIPTION	Engine takes excessive period for reaching normal operating temperature.
POSSIBLE CAUSE	• Thermostat malfunction • Cooling fan system malfunction


STEP	INSPECTION	RESULTS	ACTION
1	Is the only customer complaint "Lack of passenger compartment heat"?	Yes	Inspect A/C and heater system.
1		No	Go to the next step.
2	Does the engine speed remain at fast idle?	Yes	Go to symptom troubleshooting "No.9 FASR IDLE/RUNS ON". (See NO.9 FAST IDLE/RUNS ON [YF (2.0L Zetec)].)
2	Does the engine speed remain at fast idle?	No	Go to the next step.
3	Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [YF (2.0L Zetec)].) (See THERMOSTAT INSPECTION [YF (2.0L Zetec), AJ (3.0L Duratec)].) Is the thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat.
4	Inspect cooling fan control system operation. (See Cooling Fan Control System Operation Inspection.) Does the cooling fan control system function properly?	Yes	Access the ECT PID. Inspect both the ECT PID and temperature gauge on instrument cluster readings. • If the temperature gauge on the instrument cluster indicates normal range but the ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor. • If the temperature gauge on the instrument cluster indicates overheating but the ECT PID is normal, inspect the temperature gauge and heat gauge unit.
4		No	Repair or replace the malfunctioning part.
5	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [YF (2.0L Zetec)].) • If any malfunction remains, inspect related service information and, repair or diagnosis accordingly. - If the vehicle is repaired, troubleshooting completed. - If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [YF (2.0L Zetec)].)