NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [L8, LF, L5]

id010346802400

18

COOLING SYSTEM CONCERNS-RUNS COLD
DESCRIPTION
Engine takes excessive time to reach normal operating temperature.
POSSIBLE CAUSE
•  Thermostat malfunction
•  Cooling fan system malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
Is the customer complaint "Lack of passenger compartment heat" only?
Yes
Inspect A/C and heater system.
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 [L8, LF, L5].)
No
Go to the next step.
3
Cool down the engine.
Remove the thermostat and inspect operation.
(See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L5].)
(See THERMOSTAT INSPECTION [L8, LF, L5].)
Is the thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L5].)
4
Inspect the cooling fan control system operation.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L8, LF, L5].)
Does the cooling fan control system function properly?
Yes
Access the ECT PID.
Inspect both the ECT PID and the temperature gauge on instrument cluster readings.
•  If the temperature gauge on the instrument cluster indicates a 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 a cold range but the ECT PID is normal, inspect the temperature gauge and heat gauge unit.
No
Repair or replace the malfunctioning part.
5
•  Verify test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If the malfunction remains, inspect the related Service Information and perform 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 PCM.