your right, straight from the horses mouth, PCED
The OBD-II system monitors for malfunctions either continuously, regardless of driving mode, or non-continuously, once per drive cycle during specific drive modes. A pending DTC is stored in the PCM keep alive memory (KAM) when a malfunction is initially detected. This pending DTC may be erased on the third vehicle restart after two consecutive drives cycles with no malfunction. However if the malfunction is still present after two consecutive drive cycles, the MIL is illuminated. Once the MIL is illuminated, three consecutive drive cycles without a malfunction detected are required to extinguish the MIL. The DTC is erased after 40 engine warm-up cycles once the MIL is extinguished.