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NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [L8, LF, L3]

id0103a1802400

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

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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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". (See NO.9 FAST IDLE/RUNS ON [L8, LF, L3].)
No | Go to the next step.
3 | Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L8, LF, L3, L3 Turbo].) (See THERMOSTAT INSPECTION [L8, LF, L3, L3 Turbo].) Is thermostat normal? | Yes | Go to the next step.
No | Replace the thermostat.
4 | Inspect cooling fan control system operation. (See Cooling Fan Control System Inspection.) Does the cooling fan control system function 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 temperature gauge reading, inspect the ECT sensor. • If the temperature gauge on the instrument cluster indicates cold range but 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 diagnostic index to service any additional symptoms. (See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF, L3].) - If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle is repaired, troubleshooting completed. • If vehicle is not repaired or additional diagnostic information is not available, replace PCM. (See PCM REMOVAL/INSTALLATION [L8, LF, L3].)