Conditions For Setting DTC
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 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 36°F (20°C). If this happens, the vehicle must be driven for 5 minutes over 15 MPH. If the IAT decreases more than 12.6°F (7.0°C), a block heater is indicated and the test is aborted. If the IAT temperature does not decrease, a block heater was not detected and this DTC will set; or at the start up, the temperature difference between the ECT and the IAT is more than 252°F (140°C) and the cranking time for the engine without starting the engine is more than 10 seconds.