Conditions for Setting the DTC: P0602
WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
The PCM has not been programmed with Key On and Engine Off for one sample. Each sample is 100 milliseconds. The PCM has not been programmed at Key On and Engine Off for 0.1 second. This diagnostic runs continuously.