In view of the ever increasing electrical functions in the areas of vehicle comfort,
communication and safety, growing significance is attached to the power supply system.
In the E70, there are two separate distribution boxes. The front distribution box is near
the glove box and the rear distribution box is on the right-hand side of the luggage
compartment.
The following graphic shows the arrangement of the most important components of the
power supply system in the E70.
5
E70 Voltage Supply and Bus Systems
E70 Voltage Supply
Inde
x
Explanation
1
Rear distribution box, right-hand side of luggage compartment
2
Front distribution box behind glove compartment
System Circuit Diagram
6
E70 Voltage Supply and Bus Systems
Legend for System Circuit Diagram
7
E70 Voltage Supply and Bus Systems
Index Explanation
1
Front distribution box, behind glove compartment
2
R
ear distribution box, right hand side of luggage compartment
3
Safety battery terminal
4
Vehicle battery
5
Intelligent battery sensor (IBS)
6
Distribution box, on battery
7
Car Access System 3 (CAS 3)
8
Junction box control unit (JBE)
9
Digital Motor Electronic (DME)
10
Alternator
11
Starter
KL30
Continuous B+ (battery power)
KL30g_f
Switched positive (fault dependent)
KL30g
Switched positive, time dependent
KL15
Ignition ON
DME
DME main relay
BSD
Bit-serial data interface
K-CAN
Body
CAN
PT
-CAN
Powertrain CAN
Overview of System Components
The power supply system of the E70 consists of the following components:
• Vehicle battery
• Distribution box on the battery
• Rear distribution box on the right-hand side of the luggage compartment
• Battery cables
• Front distribution box behind the glove compartment
• Junction box control unit
• E-box engine compartment
• Jump start connection point
• Alternator.
The most important new features/changes to the power supply system in the E70 are
described below
Vehicle Battery
The vehicle battery is installed on the rear right in the luggage compartment floor.
The vehicle batteries are 70 Ah and 90 Ah batteries. Depending on the equipment,
these batteries are AGM (Absorbent Glass Mat) batteries. The main advantage of the
AGM battery is its higher cycle strength.
Distribution Box (on battery)
The distribution box in the luggage compartment of the E70 is mounted directly on the
vehicle battery. The rear distribution box on the battery is secured on the vehicle battery
by means of a metal tab. The metal tabs must be pressed downward and outward in
order to release the distribution box.
The distribution box on the battery is equipped with fuses for the following electric loads:
• Electrical auxiliary heater (100 A)
• Valvetronic or common rail system (80 A)
•
Intelligent battery sensor IBS
• Reserve
• Front distribution box (250 A)
• Rear distribution box (100 A)
• Large electric fan 850 W (100 A)
• Reserve.
8
E70 Voltage Supply and Bus Systems
The distribution box on the battery should be replaced only as a complete unit.
The fuses are integrated as a complete unit in the housing of the distribution box on the
battery. The fuses differ in terms of their power rating. The distribution box additionally
contains the power supply for the IBS.
Note: The connectors are color-coded and mechanically coded to avoid confu-
sion. These are high power connections, therefore always ensure cor-
rect contacting!
When replacing or working on the distribution box, always make sure the
plug connections and, above all, that the screw connections are secured
properly. Connection between battery terminal and distribution box
- 15 Nm.
9
E70 Voltage Supply and Bus Systems
Index Explanation
1
Battery cable to engine
2
Distribution box on battery
3
Intelligent Battery Sensor (IBS)
Index Explanation
1
Retaining clip
2
Connection to battery terminal
3
Rear distribution box connector
4
High curr
ent consumer connections
Rear Distribution Box
Due to the high number of consumers and control units in the E70, another fuse carrier
has been mounted in the luggage compartment.
In addition to the fuse carrier, relays are also plugged in or soldered onto the board.
The following relays are accommodated in the fuse carrier:
10
E70 Voltage Supply and Bus Systems
Index Explanation Index Explanation
1
T
erminal 30g relay
2
Plug connect
or
Soldered Relays (in rear distribution box)
Different relays are soldered onto the PCB in the rear distribution box. In the event of an
error, the entire distribution box must be replaced.
11
E70 Voltage Supply and Bus Systems
Index Explanation Index Explanation
1
Terminal 30 g_f relay
3
Terminal 15 relay
2
SC
A r
ela
y
Battery Cables
On the E70, two main power leads run along the underbody from the battery box to the
engine compartment. One of the main power leads is routed via the jump start terminal
to the starter and to the alternator.
The other cable supplies the engine electronics with power. Depending on the model of
vehicle, different line cross sections are used.
One battery cable is installed in the vehicle interior. It runs to the front distribution box.
The transfer points (magnified view) for the two main power cables is located in the
battery box. To avoid damage, the main power cables are installed in a protected area
on the underbody.
12
E70 Voltage Supply and Bus Systems
Cable Cross section Material
Cable to starter and alternator on N62 engine
110 mm
2
Aluminum
Cable to starter and alternator on N52 engine
90 mm
2
Aluminum
Cable to front distribution box behind glove box
35 mm
2
Copper
Cable to the motor electronics
10 mm
2
Copper
Cable to electric fan 850 W
12 mm
2
Copper
Front Distribution Box
This section describes the front distribution box. The junction box control unit is
described in the section "Junction box control unit".
There are three versions of front distribution box for the E70. In the lower part of the front
distribution box, there is an opening through which it is connected to the junction box
control unit.
Installation Position
The distribution box is installed under the instrument panel on the right-hand side.
To change a fuse, the distribution box must be lowered.
13
E70 Voltage Supply and Bus Systems
Front Distribution Box and Junction Box Control Unit
The connection between the front distribution box and the junction box control unit is
realized via the opening in the bottom of the distribution box. An internal plug connection
provides the electrical connection between the two components.
When assembled, the two components from one unit consisting of the junction box
control unit and the front distribution box.
Note: The distribution box and junction box control unit components are to be
replaced individually. In addition to the corresponding test modules in
the diagnostics, diagnosis cables are also available with which electrical
measurements can be made directly on the control-unit plugs and on the
internal interface.
14
E70 Voltage Supply and Bus Systems
Không có nhận xét nào:
Đăng nhận xét