Ford Explorer: Voltage Converter/Inverter / Description and Operation - Direct Current/Direct Current (DC/DC) Converter Control Module - System Operation and Component Description

System Operation

System Diagram - DCDC

Network Message Chart

  DCDC Network Input Messages

DCDC Operation

The DCDC is responsible for maintaining and charging the 12-volt battery. The SOBDMC sends a HEV wakeup signal to the DCDC through a hardwired circuit. For information on the high-voltage battery system,
Refer to: High Voltage Battery, Mounting and Cables - System Operation and Component Description (414-03 High Voltage Battery, Mounting and Cables, Description and Operation).

The DCDC is liquid cooled by the electric motor cooling system circuit. The electric motor cooling circuit uses an electric motor diverter valve that acts as a system thermostat, allowing the coolant to flow within the motor circuit while the motor warms. As the coolant warms, the diverter valve slowly opens to allow coolant flow to the radiator. For more information on electric powertrain cooling,
Refer to: Electric Powertrain Cooling - Overview (303-03E Electric Powertrain Cooling - 3.3L Duratec-V6 – Hybrid (BP), Description and Operation).

The DCDC communicates on the HS-CAN1 with or without the high voltage contactors closed. A wake up circuit from the SOBDMC activates the module processor. If the wake up circuit fails and high-voltage is present, the DCDC still charges but with a delay.

Faults with the DCDC that cause low or excessively high 12-volt battery voltage result in the DCDC sending a network message requesting the CHECK CHARGING SYSTEM message be displayed in the message center.

The DCDC is protected by a 30 amp high voltage low current fuse located in the high-voltage BJB. The DCDC steps the high-voltage down to a low-voltage (between 13.0 and 15.5 volts, depending on vehicle needs), providing power to the vehicle low-voltage battery systems. Depending on the vehicle and environmental conditions, the DCDC is capable of outputting as many as 165 amps to the 12-volt battery.

Component Description

DCDC

The DCDC is responsible for maintaining and charging the 12-volt battery, it communicates on the HS-CAN1.

SOBDMC

The SOBDMC provides a wake up signal to the DCDC during key on.

PCM

The PCM communicates on the HS-CAN1 and determines the ambient air temperature, enables and sets the low voltage charging setpoint, determines power pack status and transaxle gear state.

BECM

The BECM communicates on the HS-CAN1, determines the high voltage battery current flow, commands the high voltage contactors and monitors system shutdown status.

BCM

The BCM communicates on the HS-CAN1, determines the ignition state, communicates the power mode state and measures the 12-volt battery voltage with the battery sensor.