Some 2019-2021 XT4, XT5, Blazer, Acadia; 2020-2021 CT4 and CT5 models equipped with the 2.0L 4-cylinder engine (RPO LSY) may have a possible engine overheating condition along with an Engine Over Temperature message on the Driver Information Center (DIC). These conditions may be the result of an inaccurate #1 Engine Coolant Temperature (ECT) sensor. (Fig. 19)
Fig. 19
Using GDS2, confirm the accuracy of the #1 ECT sensor by comparing readings of ECT sensors 2, 3, 4, 5 and 6 to the #1 ECT sensor reading. To check the sensors, allow the engine to cold soak for several hours and then review the six ECT sensor readings (at key on, engine off) using GDS2. Verify the sensors are within a few degrees of each other. The ECT sensor readings can be compared to a like vehicle under similar test conditions with the same engine RPO option.
In addition, the resistance of the #1 ECT sensor can be measured and compared to the latest Temperature vs. Resistance chart located in the appropriate Service Information.
Data has shown that a #1 ECT sensor that is reading several degrees colder than ECT sensors 2, 3, 4, 5 and 6 could cause a potential Engine Over Temperature message to display in the DIC as well as the engine coolant temperature to operate at elevated levels.
If the #1 Engine Coolant Temperature sensor is functioning as designed, continue diagnosis according to the Service Information.
For more information, refer to #PIP5804.
– Thanks to Robert Halas
