NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF, L3]


id0103b2802400

18

COOLING SYSTEM CONCERNS -RUNS COLD

DESCRIPTION

Engine takes excessive period for reaching normal operating temperature.

POSSIBLE CAUSE

• Thermostat malfunction
• Cooling fan system malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Is 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
Remove thermostat and inspect operation.
Is thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
4
Inspect cooling fan control system operation.
Does the cooling fan control system work properly?
Yes
Access ECT PID.
Inspect for both ECT PID and temperature gauge on instrument cluster readings.
• If the temperature gauge on the instrument cluster indicates normal range but ECT PID is not the same as the temperature gauge reading, inspect the ECT sensor.
• If the temperature gauge on the instrument cluster indicates cold range but ECT PID is normal, inspect temperature gauge and heat gauge unit.
No
Repair or replace the malfunctioning part.
5
Verify test results.
• If normal, return to diagnostic index to service any additional symptoms.
• If malfunction remains, inspect related Service information perform repair or diagnosis.
- If vehicle repaired, troubleshooting completed.
- If vehicle not repaired or additional diagnostic information not available, replace the PCM.
(See PCM REMOVAL/INSTALLATION [LF, L3].)