NO.18 COOLING SYSTEM CONCERNS-RUNS COLD[LF, L3]

NO.18 COOLING SYSTEM CONCERNS-RUNS COLD[LF, L3]

id0103b2802400

18

COOLING SYSTEM CONCERNS -RUNS COLD

DESCRIPTION

Engine takes excessive period for reaching normal operating temperature.

POSSIBLE CAUSE

• Thermostat malfunction

• Cooling fan system malfunction

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	Is customer complaint "Lack of passenger compartment heat" only?	Yes	Inspect A/C and heater system.
1		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". (See NO.9 FAST IDLE/RUNS ON[LF, L3].)
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Remove thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION[LF, L3].) (See THERMOSTAT INSPECTION[LF, L3].) Is thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat.
4	Inspect cooling fan control system operation. Does the cooling fan control system work properly?	Yes	Access ECT PID. Inspect for both ECT PID and temperature gauge on instrument cluster readings. • If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor. • If the temperature gauge on the instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
4		No	Repair or replace the malfunctioning part.
5	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING[LF, L3].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION[LF, L3].)