Circuit/System Verification
- Ignition OFF, inspect the cooling system surge tank for the proper coolant level. Refer to Cooling System Leak Testing and Cooling System Draining and Filling (Static Fill) .
- Ignition OFF for 8 h or greater.
- Ignition ON, observe the scan tool IAT Sensor and ECT Sensor parameters. The ECT, IAT, and ambient temperatures should be within 6°C (11°F) of each other.
- Use the scan tool to verify the proper operation of the engine cooling system fans.
- Verify the proper heat range and the operation of the thermostat. Refer to Thermostat Diagnosis .
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
NOTE:
A critical analysis of the operation of the thermostat is necessary to properly diagnose these DTC.