Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
- Verify the condition does not exist : Incorrect fluid level or condition - Refer to Loss of Coolant (L86 L83)Loss of Coolant (L96)
- If a condition exists
Repair or replace as necessary.
- Go to next step : If no condition exists
- If a condition exists
- Verify there are no DTCs set related to the following system/component :
- B34 Engine Coolant Temperature Sensor
- {If equipped} B203 Radiator Coolant Temperature Sensor
- {If equipped} Q74 Engine Coolant Bypass Valve
- If a related DTC is set
- Go to next step : If a related DTC is not set
- Perform the following test for the appropriate component. - Engine Coolant Thermostat
- Engine Run Time - Greater than 10 min
- Increase the engine speed slowly to 3000 RPM.
- Air Conditioning - Off
- Verify the scan tool parameter : ECT Sensor = Greater than 85°C (185°F) - Within 5 min
- If 85°C (185°F) or colder
Test or replace the component : Engine Coolant Thermostat
- Go to next step : If warmer than 85°C (185°F)
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Verify the DTC does not set.
- If the DTC sets
Refer to Circuit/System Testing below
- Go to next step : If the DTC does not set
- If the DTC sets
- All OK.