Circuit Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The purpose of the accessory power module (APM), integral to the starter/generator control module (SGCM), is to control the amount and direction of energy flowing between the 42v DC and 14v DC Buses via the APM, bi-directional 42v DC to 14v DC converter. All APM functions shall only be run when in the enable mode. APM current shall be defined as the current flowing through the outputs. APM power is bi-directional, with negative current representing 14-42 direction, and positive current representing the 42-14 direction.

When the APM Power Conversion direction is set to a value of 42v to 14v, the energy shall flow from the 42v DC Bus to the 14v DC Bus via the APM. When the Service Charge or jump start is requested, the energy shall flow from the 14v DC Bus to the 42v DC Bus via the APM. When the APM Power Conversion direction is set to a value of Off, the APM shall be turned OFF and not consume or transfer any power. When the APM Power Conversion direction is set to a value of Invalid, the energy shall flow from the 42v DC Bus to the 14v DC Bus via the APM.