NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF, L5]

NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF, L5]

id010397802400

18

COOLING SYSTEM CONCERNS-RUNS COLD

DESCRIPTION

•  The engine does not reach normal operating temperature.

POSSIBLE CAUSE

•  Thermostat malfunction

•  Cooling fan system malfunction

•  PCM 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. Repair or replace the malfunctioning part according to the inspection results.
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 [LF, L5].)
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Cool down the engine. Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [LF, L5].) (See THERMOSTAT INSPECTION [LF, L5].) Is the thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [LF, L5].)
4	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF, L5].) Does the cooling fan control system function properly?	Yes	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [LF, L5].) Inspect for both the ECT PID and the low engine coolant temperature indicator light condition. • If the low engine coolant temperature indicator light on the instrument cluster turns off but the ECT PID is not same as the low engine coolant temperature indicator light condition: ― Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [LF, L5].) ― Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [LF, L5].) • If the low engine coolant temperature indicator light on the instrument cluster indicates overheating but the ECT PID is normal: ― Inspect the instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.) ― Replace the instrument cluster, if necessary. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
4		No	Repair or replace the malfunctioning part according to the inspection results.
5	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [LF, L5].) ― If a malfunction remains, inspect the related Service Information perform repair or diagnosis. • If the vehicle repaired, troubleshooting is completed. • If the vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [LF, L5].)