NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [ZJ, ZY]

id0103b0802400

18

COOLING SYSTEM CONCERNS—RUNS COLD

DESCRIPTION

•  The engine does not reach normal operating temperature.

POSSIBLE CAUSE

•  Condenser fan system malfunction

•  Cooling fan system malfunction

•  Thermostat malfunction

•  ECT sensor malfunction

•  PCM malfunction

18	COOLING SYSTEM CONCERNS—RUNS COLD
DESCRIPTION	• The engine does not reach normal operating temperature.
POSSIBLE CAUSE	• Condenser fan system malfunction • Cooling fan system malfunction • Thermostat malfunction • ECT sensor malfunction • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	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 [ZJ, ZY].)
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [ZJ, ZY].) Does the cooling fan control system work properly?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning part according to the inspection results.
4	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [ZJ, ZY].) Inspect the thermostat. (See THERMOSTAT INSPECTION [ZJ, ZY].) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [ZJ, ZY].)
4		No	Perform the PID/DATA Monitor and Record Procedure and access the ECT PID. (See ON-BOARD DIAGNOSTIC TEST [ZJ, ZY].) Inspect for both the ECT PID and the low engine coolant temperature indicator light on instrument cluster condition. • If the low engine coolant temperature indicator light on the instrument cluster indicates turned 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 [ZJ, ZY].) ― Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [ZJ, ZY].) • If the low engine coolant temperature indicator light indication on the instrument cluster illuminates 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.)
5	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [ZJ, ZY].) • If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [ZJ, ZY].)