Powertrain Control Unit, Basic Function - GF54.21-P-9894A

Engine all (4xWD, CAR) 

Overview 

This document contains information on:

• General 
  • Vehicles with hyhrid system
  • Vehicles with 48 V technology
• Function 

General 

Amongst other things, the powertrain control unit acts as an interface (gateway) between the control units that are integrated into the drivetrain.

Depending on the vehicle, the powertrain control unit communicates over the following communication paths:

• CAN bus
• FlexRay
• Ethernet

Vehicles with hybrid system

On vehicles with a hybrid system: In addition to communication with the engine electronics control unit, there is communication with hybrid-specific control units in the drivetrain and information is exchanged.

Depending on the vehicle, this can affect the following control units:

• Power electronics control unit
• Battery management system control unit
• Sound generator control unit
• Rear axle drive unit control unit (AMG vehicles)

Vehicles with 48 V technology

On vehicles with a 48 V on-board electrical system and an integrated starter alternator or belt-driven starter alternator: In addition to communication with the motor electronics control unit, there is also communication with control units relevant to the drive on a 48 V basis and information is exchanged.

Depending on the vehicle, this can affect the following control units:

• Integrated starter alternator power electronics
• Belt-driven starter alternator power electronics

Function 

The powertrain control unit primarily intervenes in the following functions:

• Drive management
• Heat management

In order to carry out these functions, the powertrain control unit processes the following input factors, among others, depending on the vehicle:

• Engine management ON (circuit 87).
• Low-temperature circuit coolant temperature.
• Status of fan motor.
• Status of accelerator pedal sensor.
• Status of start/stop button.
• Status of emergency override system control unit.
• Status of transfer case control unit
• Status of fuel system control unit
• With automatic transmission: Central communication.
• With manual transmission: Clutch travel sensor.
• Battery management system communication.
• Hybrid system communication.

The powertrain control unit processes these input variables and amongst others controls the following actuators depending on the engine variant:

• Exhaust flap controller
• Fan motor
• Radiator trim flap actuator motor
• Transmission oil cooling coolant circulation pump
• Low-temperature circuit circulation pump
• Coolant pump switchover valve