Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Yukon, 2010 Chevrolet Tahoe, and 2010 Cadillac Escalade. However, it is still accessible from the selected car via links, so may be relevant.
The Accessory Power Module (APM) controls the energy flowing between the high voltage, 300-volt, direct current (DC) and low voltage, 14-volt, DC to support the vehicles accessories and charge the 12-volt battery. The APM receives a 14-volt enable command from the Hybrid Powertrain Control Module (HPCM) over the high speed hybrid GMLAN communication circuit. APM functions will run only when the APM Enable is active on the high speed hybrid GMLAN communication circuit.