Circuit/System Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The starter/generator control module (SGCM) monitors to detect the failure of the auxiliary power module (APM) temperature sensor circuit by taking the average of the 2 power inverter module (PIM) sensors and subtracting the module temperature and looking for a difference.