1 Series E87 118d (M47T2) 5-door
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Discharge current
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Battery temperature
[more ...]
The following control units are involved in the power supply:
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JBE: Junction box electronics
The JBE is the control unit in the junction box.
The JBE is the central data interface in the vehicle (gateway for the bus systems).
[for further information, please refer to SI Technology (SBT) 61 05 04 095]
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CAS: Car access system
The Car Access System is involved in the terminal control (terminal R, terminal 15, terminal 30g).
The terminal control supplies important messages for the power supply.
The CAS is connected to the following components and control units:
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The Car Access System is connected by a direct wire to the START/STOP button and to the slot for the ID
transmitter.
The START/STOP button and the slot are located next to the steering column.
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The starter motor and the DME / DDE are connected to the CAS.
The CAS control unit is a bus subscriber on the K-CAN.
[for further information, please refer to SI Technology (SBT) 61 03 03 019]
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DME: Digital engine electronics or
DDE: Digital diesel electronics
The DME/DDE influences the power supply as follows: If the alternator voltage drops, the DME/DDE will
increase the engine speed as needed.
The software for this is called "power management".
The DME/DDE is connected to the PT-CAN (Powertrain Controller Area Network) as part of the bus system.
If an intelligent battery sensor is fitted, the DME / DDE will evaluate the current battery condition. In this way, the
DME / DDE also influences terminal 30g-f (see below under "System functions").
[more in Technical Service Information (SBT) 11 01 04 068]
[for further information, please refer to SI Technology (SBT) 11 06 04 117]
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MRS: Multiple restraint system
The MRS control unit interrupts the power supply as follows if an accident exceeding a certain severity occurs:
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The safety battery terminal is separated from the battery.
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The electric fuel pump is switched off.
[more in SI Technical (SBT) 65 04 04 099]
The following data buses and wires are important for the power supply:
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Bitserial data interface
The bitserial data interface is the data connection between the engine control unit (DME/DDE) and the
alternator.
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2 battery cables
2 battery cables connect the battery to the engine compartment:
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One of the battery cables runs via the jump-start connection point to the starter and alternator.
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The other cable is used for the voltage supply for the fuel injection system (on spark-ignition engines:
Valvetronic, on diesel engines: Common rail system).
SBT Power supply E81, E82, E87, E90, E91, E92, E93
BMW AG - TIS
18.01.2013 18:38
Issue status (12/2007) Valid only until next DVD is issued
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