Possible Engine Overheating Condition

The turbocharged 2.0L 4-cylinder engine (RPO LSY) on some 2019 CT6; 2020-2022 CT4, CT5, XT5, XT6, Blazer, Acadia and 2021-2022 Envision models may experience an engine overheating or running hot condition. An over temperature indicator may be displayed on the instrument cluster.

Follow the engine overheating diagnostics in the appropriate Service Information if an overheating condition is present.

If the root cause of the overheating or running hot condition cannot be isolated after completing the published engine overheating diagnostics, replace the Engine Coolant Temperature (ECT) sensor #1, (Fig. 18) identified in the engine overheating diagnostic chart. The ECT sensor #1 may be reading noticeably cooler than the other ECT readings, which could affect the position of the Coolant Control Valve (CCV) and limit the amount of coolant entering the radiator. As a result, the engine may be running hot.


Fig. 18


Be sure to use the latest part listed in the Electronic Parts Catalog. Refer to the Engine Coolant Temperature (ECT) #1 – Coolant Pump Outlet Pipe procedure in the appropriate Service Information. After repairs, validate that the engine is operating in the proper temperature range.

Refer to #PIP5839 for additional information.


– Thanks to Robert Halas



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