Conditions For Setting DTC

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