For 1990-2009 cars only
- Verify that the cooling system is properly filled. Refer to Cooling System Draining and Filling .
- If the complaint is a low temperature reading, check the temperature gage for proper operation. Connect a scan tool to the vehicle and read the system temperature. Compare this reading to the temperature. Replace the gauge or switch if necessary.
- Refer to Heating Performance Diagnostic if the complaint is no heat from the HVAC system.
- Verify proper thermostat operation. Refer to Thermostat Diagnosis .
