Conditions for Setting the DTC

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 30°C (54°F) more than the IAT sensor.
OR
The ECM detects a temperature difference at power-up that indicates that the ECT sensor is 10°C (18°F) more than the IAT sensor, and the time spent cranking the engine is more than 10 seconds, when the fuel level is more than 5 percent.
OR
With the power-up IAT more than -7°C (+19°F), the ECM detects a temperature difference at power-up that indicates that the ECT sensor is 20°C (36°F) more than the IAT sensor. Then the vehicle must be driven for more than 6 minutes and 40 seconds at more than 40 km/h (25 mph). If the IAT sensor then decreases more than 4°C (7°F), an engine block heater was detected and the test is aborted. If the IAT sensor does not decrease, an engine block heater was not detected and DTC P0116 will set.