OBD-IICooling System
Cooling System Fault Codes
Engine coolant temperature, thermostat, and cooling fan fault codes.
Cooling System Codes (1)
Diagnostic Approach — Cooling System
- 1
Monitor coolant temperature with scan tool — verify it reaches operating temp.
- 2
Check coolant level and condition.
- 3
Compare ECT sensor reading to actual temperature with infrared thermometer.
- 4
Test thermostat — replace if stuck open (temp never reaches 195°F).
- 5
Check cooling fan operation — fan should cycle on at operating temp.
AI-Guided Cooling System Diagnosis
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