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".
No
Go to the next step.
3
Cool down the engine.
Remove the thermostat and inspect operation.
Is the thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
4
Inspect the cooling fan control system operation.
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.