GF54.21-P-4126RI Vehicle Power Supply Control Unit, Component Description

GF54.21-P-4126RI Vehicle Power Supply Control Unit, Component Description
- except CODE (P99) Special model "AMG Black Series"

Component Identification:

Location
The vehicle power supply control unit is located in the area of the right wheel well.

Task
The vehicle power supply control unit has the following tasks:
^ Reading in of signals
^ Evaluation of input factors
^ Control of functions
^ Actuation of components

Reading in of signals
The input factors are read in via the following connection:
^ Interior CAN (CAN B)

Interior CAN
The following signals are read in over the interior CAN:
- Vehicle speed, provided by instrument cluster (A1)
- Interior temperature, provided by overhead control panel control unit (N70)
- Engine speed, provided by EZS control unit (N73)
- Circuit 61 status from front-passenger SAM control unit (N10/11)

Evaluation of input factors
The signals that have been read in are evaluated by the integrated microprocessor and the corresponding components are then actuated.

Control of functions
The vehicle power supply control unit is the master control unit for on-board electrical system management and controls the following functions:
- Recording battery state
- Controlling consumer shutoff
- Controlling battery cutoff relay (K57)
- Controlling charging of on-board electrical system battery (G1) and starter battery (G1/4)

Actuation of components
The actuation of the components takes place via the following connections:
^ Direct line
^ Interior CAN

Direct line
The following components are actuated via a direct line:
- Battery cutoff relay
- Circuit 15R/30 cutoff relay (K75)

Interior CAN
To control consumer shutoff, the vehicle power supply control unit transmits corresponding messages requesting a reduction in power output or consumer shutoff in a defined sequence on the interior CAN. The following control units receive these signals:
- Instrument cluster
- PSE controller unit with combined functions (A37)
- COMAND operating, display and control unit (A40/3)
- Rear SAM control unit (N10/8)
- Driver-side SAM control unit (N10/10)
- Passenger-side SAM control unit
- AAC [KLA] control and operating unit (N22)
- Left front seat adjustment control unit with memory (N32/1)
- Right front seat adjustment control unit with memory (N32/2)
- RVC control unit (N52)
- PTS control unit (N62) (with code (220) PARKTRONIC)
- Left door control unit (N69/1)
- Right door control unit (N69/2)
- KEYLESS-GO control unit (N69/5) (with code (889) Keyless Go)
- Overhead control panel control unit
- EIS [EZS] control unit
- Central gateway control unit (N93)

The EIS (EZS) control unit sends the signal to the engine compartment CAN (CAN C). The following control unit receives the signal over the engine compartment CAN:
- ME-SFI [ME] control unit (N3/10)

The central gateway control unit makes the signal available on the engine compartment CAN. The following control unit receives the signal over the engine compartment CAN:
- ESP, SPS [PML] and BAS control unit (N47-5)

Design
The vehicle power supply control unit consists of actuation/ evaluation electronics and an output unit with DC/DC converter which are accommodated in a metal housing.