Repair manual

ManualsBrandsBMW ManualsOther3 ELECTICAL SYSTEM

Initial Print Date: 03/05
Table of Contents
Subject Page
Vehicle Electrical System  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Battery Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Rear Power Distribution  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Battery Safety Terminal  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Intelligent Battery Sensor (IBS)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
IBS Measuring /Evaluation Function . . . . . . . . . . . . . . . . . . . . . . . .10
Servicing the IBS  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
IBS Diagnosis  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Voltage Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Current Measurement  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Terminal 15 Wake-up Signal Faults  . . . . . . . . . . . . . . . . . . . . . . . .12
IBS Wake-up  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Vehicle Ground Points  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Junction Box  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Distribution Box  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Junction Box Electronic Control Module (JBE) . . . . . . . . . . . . . . . . . . . .19
Bus Systems  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
K-Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
K-Bus (protocol)   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
LIN-Bus  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
BSD  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Terminating Resistors  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
MOST Bus  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Light Direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Fiber Optics Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Identification of Fiber Optics Conductors  . . . . . . . . . . . . . . . . . . .29
Diagnosis Information  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Data Flow Interruption  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Overtemperature Shut-Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Power Management  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Power Consumption During Operation . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Idle Speed Boost  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
E90 Voltage Supply & Bus Systems
Revision Date:

Summary of content (46 pages)

PAGE 1
Table of Contents E90 Voltage Supply & Bus Systems Subject Page Vehicle Electrical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Battery Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Rear Power Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PAGE 2
Subject Page Electric Load Reduction - Engine Running . . . . . . . . . . . . . . . . . . . . .34 Electric Load Cut-Off with Engine Off . . . . . . . . . . . . . . . . . . . . . . . . .35 Terminal 30g Relay (Time-Dependent Deactivation) . . . . . . . . . .36 Terminal 30g_f Relay (Fault-Dependent Deactivation) . . . . . . . .37 Terminal 30 (KL30) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 Terminal 15 (KL15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PAGE 3
Voltage Supply & Bus Systems Model: E90 Production: From Start of Production After completion of this module you will be able to: • Understand the power distribution function • Explain the Power Management function • Diagnose current draw situations • Identify importance of Junction Box • Understand the vehicles bus structure 3 E90 Voltage Supply & Bus Systems
PAGE 4
Vehicle Electrical System Introduction The voltage supply system on the E90 uses a Junction Box (JB) with a control module as a primary power distribution point and bus system gateway. To ensure balanced energy management in the vehicle an energy management function similar to that used in the E60 is utilized and is incorporated into the operating software of the DME.
PAGE 5
Battery Connections Located on the right side of the luggage compartment is the battery, from here power is supplied to the starter, alternator, engine electronics and to the junction box by way of three main supply cables. 1 2 1. One main cable is routed on the interior of the vehicle along the right side, to the junction box located behind the glovebox. 2.
PAGE 6
Rear Power Distribution Attached directly to the top of the battery is the rear power distribution box which contains the fusible links (non replaceable) used to distribute power to the Junction Box and Engine Electronics, plus supply power to the Intelligent Battery Sensor (IBS).
PAGE 7
Battery Safety Terminal The Battery Safety Terminal (BST) is used to reduce the risk of a short circuit to the B+ terminal of the battery in the event of an accident, as a result of a short circuit on the cable running from the B+ terminal of the battery to the Starter & Alternator (an unfused/unprotected circuit) .
PAGE 8
Intelligent Battery Sensor (IBS) The Intelligent Battery Sensor (IBS) as a mechanical/electronic device which is connected directly to the negative battery terminal.
PAGE 9
The IBS is able to withstand thermal loads up to 105°C, the chemical effects of the battery acid. The components of the IBS are shown below: Index Explanation Index Explanation 1 Copper 4 Injection Molding/Housing 2 Gullwings/Tabs 5 Copper 3 PC Board with Evaluation Electronics 6 *Manganin *Manganin - Is a copper alloy resistor with a low resistance value, that is able to maintain an extremely constant temperature regardless of current flow.
PAGE 10
IBS Measuring /Evaluation Function The measuring/evaluation function of the IBS electronics, continuously measures the following values under all vehicle operating conditions: • Voltage (6 V to 16.5 V) • Starting Current (0 A to 1000 A) • Current (200 A to +200 A) • Temperature (-40°C to 105°C) • Closed Circuit Current (0 A to 10 A) When the vehicle is stationary, the IBS is programmed to wake up every 14 sec. and makes the required measurements within approx. 50 ms in order to save power.
PAGE 11
Servicing the IBS The IBS is very sensitive to mechanical stress and strain. It is serviced as a complete unit with the ground cable. The ground cable also serves as a heat dissipater for the IBS.
PAGE 12
Terminal 15 Wake-up Signal Faults The IBS recognizes wake-up line faults. The IBS can detect a wake-up line error under the following conditions: • DME “ON” • Terminal 15 “ON” (voltage high at IBS) • Terminal 15 running via BSD If Terminal 15 at the IBS and Terminal 15 via the BSD are not equal, a fault is indicated in the BSD line or an IBS Fault.
PAGE 13
X X X X X X X X X X X X X X X X X Vehicle Ground Points 13 E90 Voltage Supply & Bus Systems
PAGE 14
Classroom Exercise - Review Questions 1. What components make up the rear power distribution? 2. What information is recorded by the IBS? 3. Information from the IBS is transmitted to where? Via what path? 4. Why does the IBS send a wake-up signal? What module wakes up? 5.
PAGE 15
NOTES PAGE 15 E90 Voltage Supply & Bus Systems
PAGE 16
Junction Box On the 3 series (E90) the Junction Box (JB) plays a central role in the distribution of power to the various components installed in the vehicle. Based on the equipment level installed in a vehicle the JB may be “configured” differently. For us vehicles only one variant will be available.
PAGE 17
Within the distribution box itself fuses and relays are plugged directly into the PC board as well as directly into the wiring harness.
PAGE 18
The upper left corner of the junction box provides an interface connection directly to the vehicle wiring harness for the purpose of relay activation and supplying power to various loads. Pin Explanation Pin Explanation 1 Secondary Air Pump Activation (Gnd) 6 Activation Term. 30g (Gnd) 2 ------ 7 Ground 3 Terminal 87, DME Secondary Air Pump 8 ------ 4 Activation of Electric Fuel Pump, (Gnd) 9 Working current, wiper stage 1 5 Activation Term.
PAGE 19
Junction Box Electronic Control Module (JBE) Not only does the Junction Box serve as a power distribution center it also provides additional functions as a result of having an Electronic Control Module.
PAGE 20
The Distribution Box interface/connection point (X4010) to the Electronic Control Module is located in the lower left corner of the Junction Box Interface/Connection Point (X4010): 1 10 11 20 23 Pin Explanation Pin Explanation 1 Diagnosis, Rear Window Defogger 13 Term. 30g_f, switch-on (Gnd) 2 Diagnosis, Rear Window Wiper 14 Activation, Wiper Stage 1 (Gnd) 3 Term.
PAGE 21
Classroom Exercise - Review Questions Junction Box 1. What function does the Junction Box serve? 2. What function does the Junction Box Electronics control module serve? 3. What relays are soldered to the circuit board? 4.
PAGE 22
Bus Systems The bus structure in the new BMW 3 Series (E90) builds on the technology being used in the current models . In the E90 the Junction Box Electronic Control Module (JBE) serves as the Gateway Module for the bus system, meaning that the JBE is the connection point for the K-CAN, PT-CAN and D-Bus. The Junction box only serves a pass through function for the F-CAN, data is not transferred by the JB to other systems for this bus.
PAGE 23
Main bus systems are responsible for the data exchange between the control modules throughout the vehicle system. Example: The status of the door contacts is read in via the Footwell Module (FRM) when the doors are locked on the BMW 3 Series. The information is transmitted via the K-CAN to the Junction Box Control Module which in turn activates the central locking drive units. Sub-Bus systems are used to exchange relatively small quantities of data within one defined system.
PAGE 24
E90 Voltage Supply & Bus Systems 2x 2x CA CAS2 PDC IHKA MRS5 CON CID FZD SMFA USIS Kombi FRM ELV TAGE OC3 2x CDC TCU TOP-HIFI Bus System Overview - E90 U.S.
PAGE 25
Legend for Bus System Overview - E90 U.S.
PAGE 26
K-Bus The K-Bus serves the purpose of linking the OC3 mat (Seat Occupancy Recognition) to the MRS 5 Control Module. K-Bus (protocol) The term "K-Bus (protocol)" is used for a series of sub-bus systems for various purposes. The K-Bus protocol used here is a common component used in previous models.
PAGE 27
MOST Bus The new 3 series (E90) uses a MOST-Bus structure, similar to that used on E60/61/63/64/65/ & E66, as a means of connecting the Information and Communication Systems (IKT). MOST is a data bus technology developed & standardized for automotive applications and stands for Multimedia Oriented System Transport. Devices connected on the MOST bus use light pulses to communicate/transmit data from one device to the other. The communication on a MOST-Bus structure is only in one direction around the ring.
PAGE 28
Light Direction Each control module on the MOST-Bus is able to send data, however it can only be sent in one direction. The physical light direction is from the master controller (Rad2 or CCC) to the fibre optics connector (located in rear of vehicle) and from here to the control modules in the luggage compartment (CD Changer, Top HiFi Amplifier, TCU, SDARS etc.). From the last control module, the light returns via the MOST-direct access port to the master controller.
PAGE 29
Fiber Optics Connector The use of a fiber optics connector provides the advantage of being able to easily retrofit control modules in the area of the luggage compartment. The fibre optics connector is located behind the left-rear lateral seat back trim panel, next to the rear seat backrest. A cable duct is provided in addition to the fiber optics conductor to avoid excessively small radii (bends) in the fiber optic conductors.
PAGE 30
Diagnosis Information Data Flow Interruption Several factors can cause an interruption in the data flow in the MOST-Bus: • Power supply of transmitting control module defective • Internal fault in transmitting control module • Transmitter in transmitting control module defective • Power supply of receiving control module defective • Internal fault in receiving control module • Receiver in receiving control module defective • Break in the fiber optics conductor between transmitting and receiving module With
PAGE 31
NOTES PAGE 31 E90 Voltage Supply & Bus Systems
PAGE 32
Classroom Exercise - Review Questions Bus Systems 1. What module serves as the main gateway? 2. What module(s) serve as the controller/gateway for the MOST-Bus? 3. Identify the various bus structures and what role they have. 4. What are terminating resistors? 5.
PAGE 33
Power Management A power management function some what similar to that used in the E60 is also used in the E90 to ensure balanced power/energy distribution in the vehicle. The power management functions are incorporated into the software of the Engine Control Module (ECM/DME).
PAGE 34
Power Consumption During Operation During vehicle operation, the mechanical energy of the engine is converted by the alternator into electrical energy and made available to the various electric loads. The electric loads receive power primarily via the terminal 30g and 30g_f relays located in the junction box. Certain electric loads are supplied directly by terminal 30 or by terminal R. For example, the anti-theft alarm system must still remain active when the vehicle is parked.
PAGE 35
Electric Load Cut-Off with Engine Off Certain electric loads may be active although the engine is off and the closed-circuit current monitoring feature of the power management function is in operation. The electric loads in the vehicle are divided into the following groups: – Legally required electric loads (i.e. side lights, hazard warning system) – Convenience for the customer (i.
PAGE 36
Terminal 30g Relay (Time-Dependent Deactivation) The terminal 30g relay is controlled by the CAS, which switches off the connected control modules after 30 minutes if the engine was running for an extended period. The switch of time is extended to 60 minutes if a telephone system is installed in the vehicle. The terminal 30g relay is controlled by the car access system and supplies power to the systems indicated below.
PAGE 37
Terminal 30g_f Relay (Fault-Dependent Deactivation) The Junction box control module controls the 30g_f terminal, which is primarily a terminal 30 circuit that is only switched off if a fault is detected. A bistable relay is used to control terminal 30g_f by means of two coils, one to open the circuit and one to close it, each coil is controlled by the Junction Box control module. Each coil is supplied directly by KL.30, the JB control module grounds the respective coil in order to open or close the relay.
PAGE 38
Terminal 30g_f is switched ON with: • Vehicle unlocked • Terminal change from R “Off” to R “On” or terminal 15 • Change in contact status for the trunk, hood or any door Note: The relay only needs to be switched on if it was previously turned off, otherwise the relay is in the “On” position. Terminal 30g_f is switched OFF when: • With terminal R off, the DME detects, via the IBS, that the starting capability limit has been reached (battery capacity is just enough to start the vehicle).
PAGE 39
Terminal 30 (KL30) A number of control modules are connected to terminal 30 via the junction box.
PAGE 40
Terminal 15 (KL15) The only module on the BUS effected by Terminal 15 relay is the PDC Control Module. The terminal 15 relay in the Junction Box is deactivated by the CAS.
PAGE 41
System Diagnosis Information The control modules for the DME/ECM and Junction Box (JB) provide various forms of information for the purpose of establishing effective system & Battery diagnosis: DME/ECM stores various data that can be used for energy diagnosis, such as: • With an IBS installed the last 32 cycles of closed circuit current monitoring data are stored • Last registered battery replacement • Accumulated mileage over past five days The Junction Box Electronics stores information pertaining : • Max
PAGE 42
Closed Circuit Current The closed-circuit current on the E90 is: • Approx. 22 mA on fully equipped US vehicles. A check control message is displayed if a closed-circuit current value of 80 mA was encountered while the vehicle was stationary. The following diagrams show a typical closed-circuit current progression for the E90 in connection with the various operating modes of the vehicles electrical system, with vehicle secured and not secured.
PAGE 43
Transport Mode The following functions are switched off and on in the E90 when vehicle is placed into transport mode. Index Function Module Transport Mode (O-On/X-Off) 1 Mirror heater (driver's door) FRM X 2 Mirror heater (passenger's door) FRM X 3 Follow-me-home" lighting " FRM X 4 Side light FRM X 5 Parking light FRM X 6 Interior light FRM O 7 Limiting VA/IB time from 16 min to 1 min (interior light, reading light, luggage compartment light etc.
PAGE 44
Transport Mode Cont.
PAGE 45
Workshop Exercise - Power Management Identify/Highlight specific control modules related to the following requests. Identify the control modules located on the terminal 30g circuit. (refer to page 36) Identify the control modules located on the terminal 30g_f circuit. (refer to page 37) Identify the control modules located on the terminal 30 (KL30) circuit.
PAGE 46
Classroom Exercise - Review Questions 1. Under what conditions is the circuit for term.30g_f switched off? 2. Describe the operation of relay 30g_f. What controls it? 3. When is terminal 30g switched off? 4. For U.S. vehicle what should the current draw be in sleep mode? (approx.) 5.