Conditions For Setting DTC

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

If the ECM detect a temperature difference between the ECT sensor and the IAT sensor of more than 252°F (140°C) at start up.
The time spent cranking the engine, without starting is more than 10 seconds with a temperature difference between the ECT sensor and the IAT sensor more than 36°F (20°C).
If the ECM detects a temperature between the ECT sensor and the IAT sensor of more than 36°F (20°C), then the vehicle must be driven for 5 minutes over 15 MPH. If the IAT sensor temperature decreases more than 12.6°F (7°C), then a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, then a block heater was not detected and DTC P0116 sets.