Silverado 1500 2WD V8-6.0L Hybrid (2009)
Drive Motor Control Module: Description and Operation
Drive Motor Generator Control Module Description and Operation
Overview
The drive motor generator power inverter module (PIM) assembly converts high voltage direct current (DC) electrical energy to 3 phase alternating
current (AC) electrical energy. The accessory DC power control module (APM) converts high voltage DC electric energy into low voltage (14V) and
intermediate voltage (42V) in order to charge the vehicles accessory battery and supply electric energy to the 42V power steering system. The APM and
PIM are fastened together and are referred to as the drive motor generator control module assembly. The drive motor generator control module assembly
is cooled with pre-mixed Dexcool(R) circulating through a cooling system that is separate from the engine cooling system. The hybrid cooling system
utilizes a heat exchanger at the front of the vehicle and electric pumps to circulate the coolant. The engine control module (ECM) monitors a temperature
sensor in the hybrid cooling system and operates the radiator fan and the hybrid coolant pumps in response to system temperature.
High Voltage Circuits
Direct Current (DC)
The drive motor generator control module assembly is connected to each pole of the high voltage (HV), direct current (DC) drive motor generator
battery. Both of the negative and positive HV DC battery poles are isolated from the vehicle chassis by a specific amount of resistance. Each HV DC
cable is switched ON or OFF by a high voltage, high current contactor relay contained within the drive motor generator battery assembly. All HV DC
negative and positive DC cables are individually shielded and orange in color to alert the technician to the potential presence of high voltage. The
electric air conditioning compressor high voltage DC cables are externally connected at the drive motor generator control module assembly. The APM
and PIM share an internal connection that supplies the APM with high voltage DC current.
Three Phase Alternating Current (AC)
Three cables connect each motor generator to the PIM. Each individually shielded cable is orange in color to alert the technician to the potential
presence of high voltage.
Intermediate and Low Voltage Circuits
The APM converts high voltage 300V DC current into both intermediate voltage, 42V, and low voltage, 12V, current.
Intermediate Voltage 42V Direct Current
Intermediate voltage 42V cables are individually shielded and are blue in color to alert the technician to the potential presence of intermediate voltage.
Low Voltage (12V) Direct Current
Low voltage (12V) cables on the hybrid-electric vehicle do not require unique coloring or servicing procedures.
Drive Motor Generator Power Inverter Module (PIM) Assembly
Overview
Contained within the PIM assembly are the hybrid powertrain control module (HPCM), and two motor control modules (MCM). Each MCM controls its
respective motor generator. All three modules are flash-programmable micro-processors.
Hybrid Powertrain Control Module (HPCM)
Location
The HPCM is a non-serviceable, flash-programmable micro-processor contained within the PIM assembly.
Operating Functions
The HPCM is the main controller of hybrid operation. The HPCM determines when to perform hybrid operation modes such as engine Auto-stop and
regenerative braking. The HPCM also operates in conjunction with the battery energy control module (BECM) to determine when to enable and disable
the DC high voltage circuits. Each MCM operates the applicable electric motor generator based upon HPCM commands.
Communication and Hosted Diagnostics
The HPCM is the host controller for diagnostic trouble code (DTC) information for the following control modules:
