NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [13B-MSP]

id0103f2802400

18

COOLING SYSTEM CONCERNS-RUNS COLD

DESCRIPTION

The engine takes excessive time to reach the normal operating temperature.

POSSIBLE CAUSE

•  Thermostat malfunction

•  Eccentric shaft bypass malfunction (stuck open)

•  Cooling fan system malfunction

18	COOLING SYSTEM CONCERNS-RUNS COLD
DESCRIPTION	The engine takes excessive time to reach the normal operating temperature.
POSSIBLE CAUSE	• Thermostat malfunction • Eccentric shaft bypass malfunction (stuck open) • 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 system.
1		No	Go to the next step.
2	Does the engine speed continue at fast idle?	Yes	Go to the symptom troubleshooting "No.9 Fast idle/runs on". (See NO.9 FAST IDLE/RUNS ON [13B-MSP].)
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [13B-MSP].) (See THERMOSTAT INSPECTION [13B-MSP].) Is the thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat.
4	Inspect the cooling fan control system operation. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [13B-MSP].) Does the cooling fan control system work properly?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning part.
5	Access the ECT PID. Inspect readings on both the ECT PID and the temperature gauge on the instrument cluster. Is the ECT PID indication the same as the temperature gauge readings?	Yes	Inspect the eccentric shaft bypass valve.
5		No	If the temperature gauge is in the normal range but the ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [13B-MSP].) If the temperature gauge on the instrument cluster indicates the cold range but the ECT PID is normal, inspect the temperature gauge and the sending unit. (See INSTRUMENT CLUSTER INSPECTION.)
6	• Verify test results. ― If normal, return to the diagnostic index to service any additional symptoms. ― If the malfunction remains, inspect related the Service Bulletins and/or the On-line Repair Information and perform the repair or diagnosis.