BMW 3 ELECTICAL SYSTEM- Manuals

6 E90 Voltage Supply & Bus Systems Rear Power Distribution Attached directly to the top of the battery is the rear power distribution box which con-tains the fusible links (non replaceable) used to distribute power to the Junction Box andEngine Electronics, plus supply power to the Intelligent B...

7 E90 Voltage Supply & Bus Systems 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 thecable running from the B+ terminal of the battery to the S...

9 E90 Voltage Supply & Bus Systems The IBS is able to withstand thermal loads up to 105°C, the chemical effects of the bat-tery acid. The components of the IBS are shown below: *Manganin - Is a copper alloy resistor with a low resistance value, that is able to maintain an extremely constant temp...

10 E90 Voltage Supply & Bus Systems IBS Measuring /Evaluation Function The measuring/evaluation function of the IBS electronics, continuously measures the fol-lowing values under all vehicle operating conditions: When the vehicle is stationary, the IBS is programmed to wake up every 14 sec. andm...

11 E90 Voltage Supply & Bus Systems Servicing the IBS The IBS is very sensitive to mechanical stress and strain. It is serviced as a complete unitwith the ground cable. The ground cable also serves as a heat dissipater for the IBS. Particular attention should be paid to the following points in s...

12 E90 Voltage Supply & Bus Systems Terminal 15 Wake-up Signal Faults The IBS recognizes wake-up line faults. The IBS can detect a wake-up line error underthe following conditions: • DME “ON” • Terminal 15 “ON” (voltage high at IBS) • Terminal 15 running via BSD If Terminal 15 at the IBS and Ter...

13 E90 Voltage Supply & Bus Systems Vehicle Ground Points X X X X X X X X X X X X X X X X X

14 E90 Voltage Supply & Bus Systems 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...

On the 3 series (E90) the Junction Box (JB) plays acentral role in the distribution of power to the variouscomponents installed in the vehicle. Based on theequipment level installed in a vehicle the JB may be“configured” differently. For us vehicles only one vari-ant will be available. Contained in ...

19 E90 Voltage Supply & Bus Systems Junction Box Electronic Control Module (JBE) Not only does the Junction Box serve as a power distribution center it also provides addi-tional functions as a result of having an Electronic Control Module. The electronic controlmodule is the Gateway Module for t...

21 E90 Voltage Supply & Bus Systems Classroom Exercise - Review QuestionsJunction 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. What systems do the relays on the JBE ...

The bus structure in the new BMW 3 Series (E90) builds on the technology being usedin 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 connec-tion point for the K-CAN, PT-CAN and D-Bus. The Ju...

23 E90 Voltage Supply & Bus Systems Main bus systems are responsible for the data exchange between the control modulesthroughout 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...

24 E90 Voltage Supply & Bus Systems WUP FS MOS T PT -C AN BSD LIN-B us D-B us K-C AN F-C AN K-B us (pr ot ocol) 8x JBE SBF A RLS FRM CID Ko m bi CON CDC T O P -HIFI USIS SINE SMF A FZD MRS5 PDC IHKA CA EL V TA G E SMC ASP 2x 2x SH TC U SD ARS CCC RAD2 2x OC3 CA S 2 LDM A CC II DSC EGS DSC-SEN LW...

26 E90 Voltage Supply & Bus Systems K-Bus The K-Bus serves the purpose of linking the OC3 mat (Seat Occupancy Recognition) tothe 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...

27 E90 Voltage Supply & Bus Systems MOST Bus The new 3 series (E90) uses a MOST-Bus structure, similar to that used onE60/61/63/64/65/ & E66, as a means of connecting the Information and CommunicationSystems (IKT). MOST is a data bus technology developed & standardized for automotive app...

28 E90 Voltage Supply & Bus Systems Light Direction Each control module on the MOST-Bus is able to send data, however it can only be sentin one direction. The physical light direction is from the master controller (Rad2 or CCC) to the fibre opticsconnector (located in rear of vehicle) and from h...

29 E90 Voltage Supply & Bus Systems Fiber Optics Connector The use of a fiber optics connector provides the advantage of being able to easily retrofitcontrol modules in the area of the luggage compartment. The fibre optics connector islocated behind the left-rear lateral seat back trim panel, ne...

30 E90 Voltage Supply & Bus Systems 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 contr...

32 E90 Voltage Supply & Bus Systems Classroom Exercise - Review QuestionsBus 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...

33 E90 Voltage Supply & Bus Systems 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 man-agement functions are incorporated into the software of the Engine Control Module(ECM/DME)....

34 E90 Voltage Supply & Bus Systems Power Consumption During Operation During vehicle operation, the mechanical energy of the engine is converted by the alter-nator into electrical energy and made available to the various electric loads. The electricloads receive power primarily via the terminal...

35 E90 Voltage Supply & Bus Systems Electric Load Cut-Off with Engine Off Certain electric loads may be active although the engine is off and the closed-circuitcurrent monitoring feature of the power management function is in operation. The electric loads in the vehicle are divided into the foll...

37 E90 Voltage Supply & Bus Systems Terminal 30g_f Relay (Fault-Dependent Deactivation) The Junction box control module controlsthe 30g_f terminal, which is primarily aterminal 30 circuit that is only switchedoff if a fault is detected. A bistable relay is used to control terminal30g_f by means ...

38 E90 Voltage Supply & Bus Systems 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, oth- erwise th...

41 E90 Voltage Supply & Bus Systems System Diagnosis Information The control modules for the DME/ECM and Junction Box (JB) provide various forms ofinformation for the purpose of establishing effective system & Battery diagnosis: DME/ECM stores various data that can be used for energy diagnos...

42 E90 Voltage Supply & Bus Systems 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 wasencountered while the vehicle was stationary. The following diagr...

43 E90 Voltage Supply & Bus Systems Transport Mode The following functions are switched off and on in the E90 when vehicle is placed intotransport 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-ho...

45 E90 Voltage Supply & Bus Systems 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 ...

46 E90 Voltage Supply & Bus Systems 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 ...