Conditions For Setting DTC
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
The PCM may detect a temperature difference between the ECT and the IAT of more than 180°F (100°C).
The time spent cranking the engine, within starting is more than 5 seconds with a temperature difference between the ECT sensor and the IAT sensor of more than 27°F (15°C).
The PCM detects a temperature difference between the ECT sensor of more than 27°F (15°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.