BMW 3: Equipotential bonding
The low-resistance connection between the housing of the high-voltage battery
unit and ground is
a crucial prerequisite for the fault-free function of the integrated isolation
monitoring. This is why it
is important to observe the correct tightening torque for all assembly screws.
It is also important to
ensure that neither the housing of the high-voltage battery unit nor the body at
the respective bore
holes/threads is painted, corroded or dirty. The bare metal must be exposed if
necessary before the
assembly screws can be mounted.

If the low-resistance connection between the high-voltage battery unit
and the body ground is
insufficient, then a possible isolation fault remains unnoticed and cannot be
detected by the isolation
monitoring. In the event of a fault, there is the potential danger of an
electric shock.

When mounting the mounting bolts and equipotential bonding screws, the exact
procedure must be
observed:
- Clean contact surfaces and screw hole threads and have them checked by a
second person
- Tighten assembly screws to specified torque
- Have torque checked by second person
- Both persons must record this in the vehicle records for the correctness
of the version. The
"Form for equipotential bonding screw connections" is provided in ISTA
application for
this purpose.
System wiring diagram

G20 PHEV, system wiring diagram for high-voltage battery unit in the
high-voltage network
- Electric A/C compressor (EKK)
- Electrical heating
- Electric motor
- High voltage disconnect (rescue disconnect)
- Electric Motor Electronics (EME)
- Evaluation circuit for test signal of the high-voltage interlock loop in
the
Electrical Machine Electronics
- Advanced Crash Safety Module (ACSM)
- High-voltage safety connector ("Service Disconnect")
- Voltage supply for power distribution box, rear right (30B)
- Intelligent battery sensor (IBS2)
- Auxiliary battery
- Safety battery terminal (SBK2)
- Clock generator for the test signal of the high-voltage interlock loop
in the
battery management electronics (SME)
- Evaluation circuit for test signal of the high-voltage interlock loop in
the battery
management electronics (SME)
- Battery management electronics (SME)
- Cell modules of the high-voltage battery unit
- Electromagnetic switch contactor
- High-voltage battery unit
- Convenience charging electronics (KLE)
- Charging socket
READ NEXT:
High-voltage interlock loop
The SME control unit evaluates the signal of the high-voltage interlock loop
and checks whether there
is an open circuit with this circuit. In the event of an open circuit
Three signs are attached to the housing of the high-voltage battery unit: 1
type plate and 2 warning
stickers. The type plate provides logistical information (e.g. part number) and
the key technical
SEE MORE:
General information
This chapter describes functions that are operated
in a different way to the way they are operated
in the front, or are only available in the rear.
Music hard disk
Saving of music via CD/DVD is only possible
in front.
The export and import of data is only possible
via the US
General information
The home address must be created to apply it as
a destination.
Defining the home address
1. Press the button on the
Controller.
2. "Set home address".
3. Enter the address.
Using the home address as the
destination
1. Press the button on the
Controller.
2. "Home".
Enter ho