Table of Contents Introduction to Advanced Body Electronics Subject Page Introduction to Advanced Body Electronics.5 Advanced Bus Systems.8 FiberOptic Bus Networks.9 Principle of Light Transmission.10 Light Attenuation.10 Causes of Excessive Attenuation .11 Bending Radius .11 Kinking.11 Compression Points .12 Stretching .12 Abrasion Points .12 Dirty or scratched Fiber Optic Cable Ends.12 Fiber Optic System Service and Diagnosis.13 Service Considerations.13 Cable Repair .13 Fiber Optic Connectors.13 Fiber Optic Diagnosis .14 MOST Bus.16 MOST Multimedia Network.16 Principle of a Multimedia Network .17 Advantages of a Multimedia Network.17 MOST Structure .17 Data Quantities.18 Functional Description .19 Data Transport.19 Optical Bus .20 Optical Transmitter.20 Optical Receiver.20 Control Unit/Control Unit Connection.21 E65 Interfaces .22 Control Display.22 Audio System Controller (ASK).22 Initial Print Date: 12/04 Revision Date: Subject Page Network Master (Main Controller).22 Audio Master.23 Connection Master.23 CD Changer Audio (CDC).24 Navigation System (NAV 01) .24 Slave (Subordinate) Control Units.24 Component Locations .24 MOST Bus Diagnosis .25 MOST Control Unit Sequence (E65).26 Optical Wave Guide Communication Fault.27 Control Module Does Not Switch Off Light.28 Network Wakeup Unsuccessful .28 Ring Break Diagnosis Carried Out (FCE190) .29 Testing.29 Light Output Reduction.29 Ring Break Test.30 Perform Ring Break Test.30 Status Wakeup.32 E65 MOST Bus Diagnostic Tips .33 Fault Symptoms E65 .33 Creating Images.34 Non-Digitized Area.34 Self-Burnt DVDs.34 Telephone E65.35 Audio .35 E60 MOST Bus Diagnosis .36 CCC/MASK.36 Diagnosis Excessive Temperature .36 Control Module Resets .36 MOST Configuration.37 Same Sequence.37 Different Sequence .37 Store Configuration .38 Ring Break Diagnosis.39 Stability Check .39 MOST Control Unit Supply.39 Repair of the MOST Fiber-Optic Cables .40 byteflight.46 Introduction.46 Design .46 Subject Page Function.47 Transmitter/Receiver Module (SE).47 Data Transmission.49 Diagnosis .49 Controller Area Network (CAN Bus).50 Introduction.50 E65 K-CAN.50 Introduction.50 K-CAN System/Peripherals .50 Advantages of two K-CAN Busses.51 Voltage Level on the K-CAN.52 Terminal Resistor .52 PT (Powertrain) CAN.54 Introduction.54 Voltage Level on the PT CAN .54 PT CAN Terminal Resistors .54 Failsafe Characteristics .55 "Wake-up" Lead in PT CAN Network.55 Diagnosis Bus.56 Introduction.56 Diagnosis Concept .57 Vehicle Diagnosis Access Point.57 Introduction to Advanced Body Electronics Model: E65, E66, E60, E63, and E64 Production: All ■micnure After completion of this module you will be able to: • Understand changes to Body Electronic Systems on the E6X models • Understand advanced bus systems • Understand Principles of Fiber Optics • Diagnose MOST Bus concerns 4 Introduction to Advanced Body Electronics Introduction to Advanced Body Electronics Beginning with the 2002 model year, a new era in on-board electronics began with the new BMW flagship - The E65. Although there were significant cosmetic changes between the last generation 7-series and the new 7, the major advances were were “under the skin”. Some of the most obvious changes were in the cockpit area. The E65 no longer used a conventional key to start the vehicle, instead a remote key fob is used in conjunction with a start/stop button. Entertainment and communications are now accessed via a single controller, which is a part of the new Drive System. Some of the design objectives on the E65/E66 included an overall reduction in control knobs and switches. This is the objective of the Drive system, to simplify the control of the various vehicle functions. To make these changes possible, new bus networks were created. For the first time, fiber optic networks were used on BMW vehicles. The 2 new bus networks are the MOST bus and the new byteflight bus. In addition to the DISplus and GT-1, there are some new tools for diagnosing system using fiber optic technology. 5 Introduction to Advanced Body Electronics As with previous 7 series introductions, the E65 platform initiated a new wave of techno¬ logical advances which were subsequently carried over to the rest of the model line. From the 2004 model year, the E60 also integrates many of the new innovations from the E65. 02290J2 The MOST and byteflight networks are still used, but modified slightly. The Drive con¬ troller is also carried over, with less overall features and an added menu button to simply operation. Kommunikation >V Klima I >li Car Data Entertainment A / A BAYERN 3 TMC O T.,ill 21:50 To continue with the advances in technology, the new E63 and E64 were introduced with some new features such as Car Computer Control (CCC) and the new Head-up Display (HUD). These 2 new features will be seen on other models as well in the near future. 6 Introduction to Advanced Body Electronics In this training course, the latest in BMW electronics technology will be covered. This course will focus on the new 5, 6 and 7 series models. This includes the following vehicle systems: • Power (energy) management • Driver information systems (Instrument cluster, Drive etc.) • Vehicle lighting systems (including LWR, AHL etc.) • Body Electronics (Power locks, windows, wipers etc.) • Vehicle warning systems (PDC, DWA and ACC) • Entertainment and Communication Systems • Seat, mirror and steering wheel functions • Head-up Display • Bus Systems • Fiber Optic technology Systems such as Passive Safety and Climate Control will be covered in their respective courses. 7 Introduction to Advanced Body Electronics Advanced Bus Systems The launch of the E65 brought about new technological innovations which reguired some advancements in bus technology. Fiber Optics, newly introduced to BMW group vehi¬ cles, allow for a larger amount of data transfer at a faster rate. There are 2 new Fiber Optic Networks used on the E65. These new networks are MOST (Media Orientated System Transport) and byteflight. MOST is used for informa¬ tion and communication systems such as navigation, audio and telephone. The new byteflight system is used exclusively for the safety system (ISIS). In addition to fiber optics, copper wire bus networks were also modified to meet the needs of the new technology. New networks such as PT-CAN and K-CAN enhanced the existing CAN bus and K-bus already in use on earlier models. Example - E65 Bus System CAS SMFA SMBF TMFAT TMBFT TM FATH TM BFTH SMFAH SMBFH HKL PM AHM PDC RDC CIM LM CON RLS SHD SH WIM Kombi HZ ASK nz TEL nz CD * CDC 1 AVT 1 LOGIC7 1 svs NAV D-BUS SZL SFZ SASL SASR STVL SSFA SIM STVR SSBF ARS DME EGS EMF GRS DSC SBSL SBSR EDC-K SSH K-CAN P K-CAN S MOST byteflight PT-CAN The K-CAN (Body Controller Area Network) replaces the single wire K-bus used on earli¬ er models. K-CAN is subdivided into two sections: K-CAN System and K-CAN Periphery. K-CAN S and K-CAN P use the two wire twisted pair configuration. The com¬ munication speed has also been increased to 100Kbps. The PT-CAN system replaces the existing CAN system. PT-CAN differs from the existing CAN system by using an additional KL-15 “wake-up” wire. Communication speed remains the same at 500Kbps. New Sub-Bus systems have also been added to provide “local” communication to the larger networks. There are several Sub Bus systems on the E65, these include the Driver’s door P-Bus, the Engine LoCAN, Telecommander CAN, M-Bus DWA K-Bus and the BSD interface. These systems will be discussed later in this course. 8 Introduction to Advanced Body Electronics Fiber Optic Bus Networks The ever-increasing level of features available in today’s automobiles require a corre¬ sponding increase in vehicle electronic systems. The transmission of data, voice and images require an efficient method to move data. Copper wire bus networks otter many advantages. However high data transmission rates in copper wires can cause electro-magnetic interference with other vehicle systems. Compared with copper wires, fiberoptic lines require less space and are lighter in weight for the same transmission band width. In contrast with copper wires, which carry digital or analog voltage signals as the means of transmitting data, fiber optic busses transmit light pulses. Fiber Optic technology has been in use in the telecommunications industry for many years. However, this type of fiber-optic cable is not practical for automotive use. These cable utilize glass based fibers which are not practical for automotive use. They are sub¬ ject to fracture from vibration and do not hold up to “tight radius” installations. POF (polymer optical fibers) were developed for the automotive industry. These fibers were developed and manufactured by Dow-Corning. Construction of Fiber Optic Cable 1 There are significant advantage to using POF fiber optic cables: • There is a low sensitivity to dust. Small amounts of contamination do not adversely affect communication. • They are easy to work with. These fibers can be bent to a radius of approximately 50mm. This allows for practical installation within the vehicle. • Processing is practical, these fibers can be cut and modified which makes the pro¬ duction of wiring looms easy. Service repairs are also made simple. • These fibers are inexpensive to manufacture and do not require expensive connec¬ tions or housings. 9 Introduction to Advanced Body Electronics Principle of Light Transmission The electrical signal generated by the control unit is converted to an optical signal by an internal transmitter module and sent along the fiber optic bus. The fiber core carries the light beam to a receiver module which converts the light signal back to a useable electri¬ cal signal. In order to prevent the light from escaping, the fiber core is enclosed by a cladding layer. The cladding is reflective and reflects light back into the core, thus making it possible to transmit light along the fiber. Light Attenuation Attenuation refers to the reduction in strength of a signal. Light transmitted along the optical fiber becomes weaker the further it has to travel. Attenuation is usually measured in decibel units (dB). In fiber optic cables, attenuation is measured in terms of the num¬ ber of decibels per unit of length (foot/meter etc). The less attenuation per unit distance, the more efficient the cable. In comparison with an electrical circuit, think of attenuation as “light resistance”. The more attenuation in the fiber optic cable, the less light output to the receiver module. The average attenuation for fiber optic bus lines is .5 decibels (dB) for each connector and .3 dB for each meter of cable. 10 Introduction to Advanced Body Electronics Causes of Excessive Attenuation Excessive attenuation can be caused by the following reasons: • Bends in the fiber optic cable with a radius of less than 50mm. • Kinks in the fiber optic cable • Squashed or compressed fiber optic cable • Damaged insulation on fiber optic cable • Stretched fiber optic cable • Dirt or grease on the exposed cable ends • Scratches on the exposed cable ends • Overheated fiber optic cable Here are some examples of various fiber optic cable failures: Bending Radius The plastic fiber optic cable should not be bent to a radius of less than 50mm. That is roughly equivalent to the diame¬ ter of a soft-drink can. Bending the cable any tighter can impair its function or irreparably damage the cable. Light can escape at points where the cable is bent too tightly. This is caused by the fact that the light beam strikes the interface between the core and cladding at too steep an angle and is not reflect¬ ed. Kinking Fiber optic cables must not under any circumstances be kinked when fitted because this damages the cladding and the fiber core. The light is partially dis¬ persed at the point where the fiber is kinked and transmission loss results. Even just kinking the cable once very briefly is enough to cause permanent damage. 11 Introduction to Advanced Body Electronics Compression Points Compression points must also be avoid¬ ed because they can permanently deform the light conducting cross sec¬ tion of the optical fiber. This would cause a loss of light. Stretching Overstretching of the fiber optic cables, caused by pulling for example, can destroy them. Stretching reduces the cross-sectional area of the fiber core. Restricted pas¬ sage of light is the end result. Abrasion Points In comparison with copper wires, abra¬ sion of fiberoptic cables does not cause a short circuit. Instead, loss of external light occurs. The system then suffers interference or fails completely. Dirty or scratched Fiber Optic Cable Ends Another potential source of problems is dirty or scratched cable ends. Although the ends of the cables are protected against accidental contact, damage can still occur by incorrect handling. Dirt on the end of an optical fiber will prevent light from exiting/entering. The dirt absorbs the light and increases attenuation. 12 Introduction to Advanced Body Electronics Fiber Optic System Service and Diagnosis Service Considerations During repair work, there are some things that need to be taken into account when working with fiber optic cables. Any paintwork which reguires the use of drying by heat, the temperature should not exceed 85°C. This could case deformation of the fiber optic cable resulting in excessive attenuation. Extreme care should be taken around fiber optic cables. Any wiring harness that contain fiber optic cables should not be subjecting to stretching, pulling or any undue stress. Cable Repair Repair cable are available for the fiber optics. The MOST bus which is normally green in the vehicle is repair using a black or orange cable. The MOST bus allows for up to one splice between control units. There are special tool for servicing and splicing the optical cables. The byteflight which is a safety critical network does not allow for any splices or repairs between control units. The entire defective optical cable must be replaced. Replacement cables are orange or black. Fiber Optic Connectors There are slight differences between the connectors on the MOST and byteflight bus. The transmitter/receiver module on the MOST bus are set back into the control unit housing. This setup allows for the protection of the delicate fiber ends of the cable. Also, MOST cable connectors are marked 1 and 2. 1 is assigned to the incoming optical fiber and 2 is assigned to the outgoing optical fiber. Typical connector used on the MOST bus components 13 Introduction to Advanced Body Electronics The byteflight bus uses a different connector configuration than MOST. Since the byteflight is connected directly to the diode, the protruding fiber end is protected by a flap. The flap is retracted when the connectors are plugged together. Typical connector used on byteflight FiberOptic Diagnosis When checking attenuation, the OPPS or OPS tester should be used in conjunction with the DISplus/GT-1. The Optical Testing and Programming System (OPPS) can be used as a substitute diagnostic head for diagnosis, or to expedite programming procedures. The OPPS can also be used to check attenuation on both the MOST or byteflight bus. The OPS is an abbreviated version of OPPS. The OPS does not have the capability to check attenuation on the byteflight bus. OPPS and OPS appear similar, but are different in color. OPPS is gray and yellow, while OPS is gray and orange. OPPS Tester (OPS not shown) 14 Introduction to Advanced Body Electronics Workshop Exercise - Fiber Optic Cable Repair Using the instructor designated fiber optic cable/connector, perform a connector /cable repair. What special tool is used to remove the sheathing from the fiber optic cable? What special tool is used to crimp the fiber optic terminal to the fiber optic cable? What is the part number of the blades used for cutting the fiber optic cable? And how many cuts are allowed per blade? What precautions should be observed when handling fiber optic cable? How many splices are allowed between two MOST bus components? How many splices are allowed between two byteflight bus components? What is the part number of the AMP butt connector? 15 Introduction to Advanced Body Electronics MOST Bus Of the 2 fiber optic networks introduced on the E65, the MOST bus is used for audio, entertainment and communication systems. MOST stands for Media Orientated Systems Transport. Starting in 1998, OEM manufacturers such as Audi, Becker, BMW and Daimler/Chrysler came together to develop a common multi-media network. As of 2001, MOSTCo (Cooperation) has approximately 65 members including all of the American and European auto manufacturers. Toyota and Nissan represent the Japanese auto industry. MOSTCo now unites about 90 percent of global automotive production and is now on track to becoming the standard for automotive multi-media services. Since the introduction of the E65, MOST has been added to the E60, E63 and E64 vehi¬ cles. MOST will also be a part of future BMW models as well. E65 TEL svs CD Fond LoaicT | AVT ASK CD 1 CDC | TV f NAV In comparison with the E38, which had only a few entertainment -related control units on the network, the E65 has a significant increase in multi-media systems. This reguires a bus network with a substantial amount of bandwidth (communication speed). The MOST bus was introduced with a data rate of 22.5 Mbps and will be increased as system needs demand. MOST Multimedia Network MOST technology meets 2 essential reguirements: • The MOST bus transports control data as well as data from audio, video navigation and other services. • MOST Technology provides a logical framework model for control of the variety and complexity of data. The MOST application framework organizes the functions of the overall system. MOST is able to control and dynamically manage functions that are distributed in the vehicle. 16 Introduction to Advanced Body Electronics Principle of a Multimedia Network An important feature of a multimedia network is that it transports not only control data and sensor data. A multimedia network can also carry digital audio and video signals and graphics as well as other data services. Information transmitted on MOST network Advantages of a Multimedia Network All data can be transported across a shared network. This offers the following benefits: • Additional signal wiring harnesses are eliminated. • The only addition many control units need is a power supply. • As each participant (control unit) has access to the data, cost intensive components for signal distribution are eliminated. Different data formats also have different requirements for transmission regarding both mechanisms (synchronous or asynchronous data) and the required bandwidth. The MOST format is able to meet these requirements to satisfactory extent. MOST Structure The MOST bus is configured in a “ring” structure. Data transmission on the ring takes place in one direction only. Messages can be transmitted provided the bus ring is com¬ plete and fully functional. A failure, such as an interruption in the ring, will cause a complete failure of the MOST ring. All modules on the MOST bus will cease to function when there is an open in the MOST bus. 17 Introduction to Advanced Body Electronics D-BUS Graphic example of “ring structure” used on MOST bus K-CANS MOST Example of MOST bus on the E65 Data Quantities The aim is that in the near future all vehicle occupants can call up different services at one time, e.g.: • The driver calls up navigation information. • The passenger talks on the telephone. • A rear seat passenger listens to a CD. • The other rear seat passenger watches a DVD video. The data guantities this reguires produce the following example: Application Band-width (data rate) Data Data Format AM/FM Check Control Audio/CD Telephone svs 1.4 Mbits/s 1 Channel Stereo Synchronous TV CD Video 1.4 Mbits/s Audio MPEG 1 Video Synchronous DVD 2.8-11 Mbits/s MPEG 2 Video Synchronous and Asynchronous Navigation 250 Kbits/s 1.4 Mbits/s 1.4 Mbits/s Vector data (arrows) MPEG 1 Video (maps) Voice commands Asynchronous Synchronous Synchronous Telematic services A few bytes Asynchronous Using MOST, there is already the capability today to transport these large data guantities. 18 Introduction to Advanced Body Electronics Functional Description Data Transport MOST currently offers a band-width of 22.5 Mbits/s . In the next generation, the band¬ width will be increased to 50 and then later to 150 Mbits/s (as of approx. 2002). In order to meet the different requirements of the applications regarding data transport, each MOST message is divided into three parts: • Control data • Asynchronous data: e.g. navigation system, arrow representation • Synchronous data: e.g. audio, video signals Data transport on the MOST bus. Different data is “packaged” and then sent as one message to be “unwrapped” by the next device on the MOST ring. Bandwidth 22,5mblT/S 44,1 kHz 23 |is A message over the MOST bus 2700 Messages The control data controls the functions and devices in the network. The information can be compared to CAN bus data. The control data has a band-width of 700 Kbit/s. That corresponds to around 2700 mes¬ sages per second. For the data transmission of synchronous and/or asynchronous data, there is a total of 60 bytes. The limit is variable: e.g. 20 bytes of synchronous data and 40 bytes of asynchro¬ nous data. 19 Introduction to Advanced Body Electronics Optical Bus The MOST bus is a plastic optical waveguide. The MOST bus is coded in green in the E65. The light wavelength is 650 nm (red light). The MOST bus reguires the following converter components: • Optical transmitter • Optical receiver Each control unit of the MOST framework contains a transmitter and a receiver. The transmitter and receiver have been developed by BMW. The low closed circuit (rest) cur¬ rent properties of the transmitter and receiver enable optical wake-up by the MOST bus. Optical Transmitter A driver is fitted in the transmitter. The driver energizes an LED (light-emitting diode). The LED transmits light signals on the MOST bus (650 nm light, i.e. red visible light). The repeat freguency is 44.1 MHz. The sensing freguency on a CD player and for audio is 44.1 MHz; this means than no additional buffer is reguired, yet another reason why this bus system is so efficient for multi-media. Optical Receiver The receiver receives the data from the MOST bus. The receiver consists of: • An LED • A pre-amplifier • A wake-up circuit • An interface that converts the optical signal into an electrical signal The receiver contains a diode that converts the optical signal into an electrical signal. This signal is amplified and further processed at the MOST network interface. 20 Introduction to Advanced Body Electronics Control Unit/Control Unit Connection The MOST ring is composed of optical point-to-point connections between 2 control units. Each control unit has a network interface. The network interface consists of: svs Network Interface Net Services Software MOST Transceiver 1 _ 1 _ _ > _ Optical Optical Receiver Transmitter 1 Navigation Network Interface Net Services Software MOST Transceiver n 1 5 r Optical Optical Receiver Transmitter 1 MOST Fiber Optic Cable • An opto-electrical converter (optical waveguide receiver, already mentioned). • An opto-electrical converter (optical waveguide transmitter, already mentioned). • A MOST transceiver (interface between the optical waveguide receiver/transmitter and the electronic network driver). • A network driver, the so-called NetServices. The NetServices run on a microcontroller (main computer in the control unit) On the application level, a control unit in the MOST framework contains stand-alone func¬ tion units, so-called function blocks. Examples of function blocks include: • Tuners • Amplifiers • CD players A control unit can contain several function blocks at one time, e.g. the AVT contains the functions: • Antenna • Amplifier • Tuner 21 Introduction to Advanced Body Electronics E65 Interfaces The following contains a brief summary of the tasks of the connected control units in the MOST framework: Control Display The Control Display is the system master of all MOST bus functions and serves as the power master. It wakes up the bus and is responsible for switching it off (power down). The DIS Plus and GT1 will show a Control Display and a Control Display (Gateway). Audio System Controller (ASK) The audio system controller has the following controller functions: Network Master (Main Controller) The ASK performs the role of network master for the MOST bus. The functions of the network master are the following: • Wake-up, initialization, power-down - The network master wakes up the bus and has the task of achieving an orderly initialization of the network. The ASK can operate with KLR off. To turn it on, push in the volume/ON/OFF knob. Adjustments and control is carried out by using the Controller and Control Display. Another task of the network master is to control the power-down process. Each power-down is initiated and started by the ASK. • Configuration control - The network master detects the exact system configura¬ tion each time that the network is started and compares it to the stored coded con¬ figuration. • Control of the network operation - The network master controls the MOST transceiver of the slave eguipment for correct operation. The eguipment which is not operating properly will be released by a reset or switched to low power mode so that they do not affect bus communication. • Fault code memory - The network master includes the fault code memory of the MOST network. It stores all the faults occurring during the network operation as well as deviations from the nominal configuration. 22 Introduction to Advanced Body Electronics Audio Master As audio master, the ASK has the task to collect and process all the audio signals of the vehicle and to distribute them to their destinations. The ASK controls all the acoustic requests from the Control Display. The changes in the level of a signal is not sudden, but smooth, e.g. during suppression, insertion and fading out or temporary suppression of the signal at the destination: Because of this, a high- quality acoustic sound is obtained. The ASK also assumes the generation and preparation of different acoustic signals, e.g. PDC signals and warnings. In the event of a request for a warning or caution signal from a control unit, the ASK provides a clean acoustic change of the signals. • Audio data - All audio data from any control unit are converted by the ASK into digital audio AF format at a sampling rate of 44.1 MHz. • Categorization of audio sources - All possible audio sources are divided into different groups according to priority. Warning signals have priority over any other audio source. Mixing of lower priority audio signals (e.g. navigation, radio) is possible. • Generation of acoustic gongs - These are acoustic alarm signals which help the dri¬ ver perceive sounds according to a system. The different sounds, requested by the different control units, (e.g. gongs, PDC, etc.), must be generated only in association with a visual indication. These come from the instrument cluster and the Control Display. The following sounds can be generated in the ASK. • Beeping for the PDC. • Various Check Control and warning gongs. Note: A maximum of three sounds can be produced at once. Sounds are pro¬ duced in order of importance. Any sound requests of greater than three will be lost. Connection Master As connection master, the ASK must provide channels to the equipment connected to the bus and distribute the audio signals on the outputs (loudspeakers). The connection master also controls the basic Hi-Fi or the LOGIC 7 Hi-Fi amplifiers. 23 Introduction to Advanced Body Electronics CD Changer Audio (CDC) The CD changer is a slave control unit in the MOST framework. Navigation System (NAV 01) The control unit of the navigation system has controller tasks and slave functions in the MOST framework. Slave (Subordinate) Control Units The following control units are slave control units: • Kombi (control unit of the instrument cluster) • AVT • LOGIC7 • SVS Speech processing system • Telephone • MMC (if eguipped - not currently used on US models) Component Locations Located in the dashboard assembly are the Control Display, Kombi, ASK, CD changer and OPPS connector. Located in the luggage compartment, rear left, are the Logic 7 Amp, SVS, NAV and TCU. Located in the C pillar left side, the AVT (Antenna Tuner) 24 Introduction to Advanced Body Electronics MOST Bus Diagnosis Due to the differences in the configuration of the MOST bus, diagnosis methods will dif¬ fer slightly between the E65/E66 and the E60, E63, E64. However, there are many simi¬ larities and there are some some basic rules which apply to all MOST equipped vehicles. The following diagnosis applies to the E65/E66 configuration and the differences will be pointed out as necessary. It is important to remember that on the MOST network, messages can only be transmit¬ ted provided the bus ring is complete and fully functional. If there is a ring fault in the MOST network, the diagnostic system only communicates with the instrument cluster and the Control Display because both of these modules are directly connected to the K- CAN System Bus. The fiber optic signals on the MOST network always travel in one direction and only in one direction. Signals always originate at the Control Display and travel to the CD chang¬ er, AVT, Logic 7 (if equipped), SVS, NAV, Multi-MediA Changer (if equipped), Telephone, ASK, Kombi and back to the Control Display. The MOST bus allows intersystem fault memory entries in the individual control modules. A feature of the system faults is that faults may be entered in a control module although the control module is OK. Conclusions may be drawn about the cause of the fault, using the fault information stored in all the control modules. The possible system faults are: • Optical wave guide communication fault (All MOST Control Module) FC 111 • A Control Module does not switch a light off (All MOST Control Modules) • Network wake-up unsuccessful (Control Display (Gateway), ASK, Telephone Only) FCE18D • Ring fault diagnosis run (Control Display (Gateway) and Kombi Only) FC El 90 The Control Display functions are split between acting as a Gateway and Displaying infor¬ mation. The Gateway function serves as the interface between the MOST and the K- CAN System buses. Although the Control Display is one control module, two control module names are displayed in the DIS Plus: • CD Control Display (MOST CAN Gateway or MCGW) • CD Control Display The faults stored in the Control Display are distributed between the Control Display Gateway and Control Display according to the function of the fault. 25 Introduction to Advanced Body Electronics MOST Control Unit Sequence (E65) ZGM Central Gateway Module K-CAN-System ASK Audio System Controller OPPS Connector H KOMBI I Cl Instrument Cluster ^1 Control C - -y CD Display CDC Audio-CD Changer Communication direction in MOST structure (E65/E66) The signal transmission direction of the MOST bus in a vehicle with full equipment takes place starting at the Control Display and travels serially towards the CD changer. Antenna Tuner, Hi-Fi amplifier, Speech processing module, Navigation, MMC (if equipped), TCU, Audio System Controller, Instrument Cluster and again back to the Control Display. I AVT Antenna Amplifier Tuner TEL Telephone Interface z Counts as 2 Counts as 2 NAVI Navigation System ▼ Logic 7 Audio Amplifier Top hi-fi svs Speech Processing System Note: Important! The component sequence of the MOST controllers in the ETM is incorrect when it comes to signal transmission direction. The correct sequence is indicated above! 26 Introduction to Advanced Body Electronics Optical Wave Guide Communication Fault This fault (FC 111) indicates a problem with optical transmission. Insufficient light is being received by one of the modules in the ring. The loss of light may be caused by: • Defective optical wave guide, Flarness twisted too tightly (Min. bend radius 50mm.) • Light output or reception sensitivity of a diode is too low • Connector not installed correctly • Voltage fluctuation while powering up a control module If the fault is stored, the system triggers a reset and starts up again. The music is switched off briefly and the display screen of the Control Display continues to operate. To find the module responsible for the fault, the fault memory of the modules must be read in MOST ring order. Fault lies between the module with the fault code (B) and the preceding module (A). If the voltage has dipped below 9v, the fault may be incorrectly stored. If the voltage is low perform the following test after connecting a battery charger. 1. Clear the fault memory in control module B. 2. Lower the light output in control module A. 3. Read out the fault memory in the MOST ring in order. 4. If control module B is again the first to store the fault, it can be assumed the fault lies between control modules A and B. Then, check control modules A and B for loose connections and check the optical wave guide for kinks. If the visual inspection is OK, the fault can be located using the OPPS tester or optionally performing the following tests. • Remove the input optical wave guide from control module B and confirm the pres¬ ence of light. If light is present, install by-pass optical wave guide in place of control module A, clear fault codes in module B and perform ring break test. If MOST net¬ work operates properly, then control module A is at fault and must be replaced. If MOST network still has a fault, put module A back in the network and by-pass module B. Clear faults and again perform ring break test. If MOST network operates now problem is with control module B and it must be replaced. • If light is not present at input of module B, perform by-pass of module A as above. The possible fault scenarios are: • Transmit diode in module A defective • Receive diode in module B defective • Optical wave guide fault between modules A and B • Software error or fault in module A or B Note: AMP butt connector p/n - 1355734-1 27 Introduction to Advanced Body Electronics Control Module Does Not Switch Off Light When the MOST network is requested to sleep, the Control Display switches off the light in the MOST ring. The lack of light input is a signal to the individual control modules to switch off their light output and enter sleep mode. If a control module does not switch off its light, all down stream control modules register the fault “A Control Module is not switching light off.” Important! Failure of a control module to turn its light off, will cause the MOST network NOT to enter sleep mode. If the MOST network fails to sleep, the rest of the car will not be able to enter sleep mode. This will lead to battery discharge. To diagnose, read out fault memory in MOST ring order. The fault lies in the control module that precedes the module where the fault is first stored. Always confirm the problem by first clearing the fault and performing the diagnosis a sec¬ ond time. If the same results occur, replace the defective control module. Network Wakeup Unsuccessful This fault indicates a problem with the optical transmission. An insufficient volume of light is coming through one position of the ring and may be caused by: • Control Module is receiving no voltage • Optical Wave Guide harness defective • Optical Element in a control module defective (transmit or receive) • Connector not installed correctly A distinction must be made as to whether the fault is currently present or sporadic. For faults currently present, run the Ring Break Diagnosis Test Plan. For sporadic faults perform the Luminous Power Reduction Test Plan. 28 Introduction to Advanced Body Electronics Ring Break Diagnosis Carried Out (FC El 90) Reading out the fault memory of the Control Display (Gateway) after performing the Ring Fault Diagnostic, results in a fault of Ring Fault Diagnosis Carried Out being stored. This fault memory is not a true fault memory entry, but only an output of additional infor¬ mation for relative node position. Testing Light Output Reduction Reducing the light output of individual control modules is a convenient method of deter¬ mining the area of a defect. • Switch on the radio. • In Control Module functions, begin to activate luminous power reduction in the individual control module. (In this test the light output of the selected control module is reduced for 5 seconds and then automatically reset to normal output) • If the optical transmission for control module A to the next control module in the ring (control module B) is OK, a slight noise may occur when the light output is reduced, however the radio will continue to play. • If the radio goes off and comes back on again(radio volume may be reduced) in 5 to 10 seconds, the optical transmission between control modules A and B is defective. If the visual inspection is OK, the fault can be located using the OPPS tester or optionally performing the following tests. • Remove the input optical wave guide from control module B and confirm the pres¬ ence of light. • If light is present, install by-pass optical wave guide in place of control module A, clear fault codes in module B. If MOST network operates properly, then control module A is at fault and must be replaced. • If MOST network still has a fault, put module A back in the network and by-pass module B. Clear faults. • If MOST network operates now problem is with control module B and it must be replaced. • If light is not present at input of module B, perform ring break diagnostics. 29 Introduction to Advanced Body Electronics Ring Break Test If there is a break in the ring (a defect between two control modules) the following fault patterns may occur: • Transmit diode of the transmitting control module defective • Power supply of the transmitting control module defective • Internal control module fault of the transmitting control module • Receiver diode of the receiving control module defective • Power supply of the receiving control module defective • Internal control module fault of the receiving control module • Optical wave guide between transmitting and receiving control module defective These faults may occur alone or in combination. To diagnose a ring break, the first step is to locate the two control modules between which the transmission failure has occurred. This is accomplished with the ring break diagnostic function. Once the two control mod¬ ules have been identified and the diagnostics have been performed, remember to check the power supply and ground circuit of both modules before condemning a module. Testing of the transmit/receive diodes will be possible using the OPPS tester. Perform Ring Break Test The ring break test mode is entered automatically when the power to all the modules in the MOST network is switched off and then switched back on. The most effective method of switching the power off and on is to disconnect the battery negative terminal for 45 seconds. This time will allow the capacitors of all the control modules to dissipate. When the battery is reconnected the control modules wake up and in MOST network order transmit a light signal to the next module. Each module checks to see if it has received a light signal from the previous module. If the control module does NOT receive a light input signal it still transmits a signal to the next module. A relative node number of 0 is stored in the control module that did not receive a signal but that transmitted one. The Control Display receives the light signal back and identifies which modules responded. Go to “Control Unit Functions” Control Display Gateway and read fault memory. 30 Introduction to Advanced Body Electronics The Control Display will display a relative node number. This number will indicate how many modules communicated after the module which set the relative node number of 0. To find the control module with the relative node number of 0, count from the input side of the Control Display (counting the Control Display as 0) towards the control modules. When arriving at the control module with the number as displayed as the relative node number in the DISplus, the last known communicating module has been found. Example: While performing the ring break diagnostics the Control Display has set a relative node number of 2. Count the Control Display a 0, the Kombi will be i and the ASK will be 2. The ring break occurs between the ASK and the module which precedes it, the tele¬ phone module. Important! When counting control modules, the multimedia changer (if eguipped) and the Nav sys¬ tem must be counted as two control modules. In order to perform the count correctly the eguipment on the vehicle must first be identified. When using the MOST network diagram in the DISplus, connector number 1 of the opti¬ cal waves are inputs and connector number 2 are outputs. 31 Introduction to Advanced Body Electronics Status Wakeup MOST control modules require high current during standby operation and must be dis¬ connected or put in sleep mode to prevent the vehicle battery from being discharged. In case of a fault on the the MOST network that continuously wakes up, the entire MOST bus will be woken up. The Control Display will wake up the CAN Bus and all the vehicle busses will be woken up. This will lead to battery discharge. It is of great benefit to know which module initiated the wake up call. In order to find out which MOST node woke up the MOST bus, the following procedure is performed - In Control Unit Functions, press “STATUS WAKEUP” Three different response are possible: • Control Module woke up • Control Module woken up • Control Module not initialized The Control Module with the status “Control Module woke up” is the module that woke up the rest of the MOST bus. This diagnosis only informs which control module woke, not the reason for the wake up, diagnostic testing should be performed on the control module and related equipment. Hints for Vehicle Equipment Identification • CDC - Look on passenger side of dashboard above glovebox. • Logic 7 - Look for speaker grills on rear doors Look on left side of trunk for large amp. • MMC - Look on left side of trunk. 32 Introduction to Advanced Body Electronics E65 MOST Bus Diagnostic Tips Fault Symptoms E65 Particularly when carrying out troubleshooting in the MOST system network it is impor¬ tant to know the precise significance of visible and audible symptoms. With this informa¬ tion it is possible to locate and correct faults much faster. The starting point for locating faults should always be to pose detailed questions relating to the fault to the customer. This information can then be used to formulate initial consid¬ eration before the BMW diagnosis system is connected. The following information should be available to the technician: • When does the fault occur? E.g. already during engine start or while driving? • Since when does the fault occur? • Does the fault depend on temperature? When cold, hot or after longer period of vehicle operation? • Do several functions fail simultaneously? If so, which? • Is the fault still present after shutting down and restarting the vehicle? • Was something switched on or off immediately before the fault occurred? • Is it necessary to enter the telephone PIN after restarting the system? • Does the radio/CD need to be switched on separately after restarting the system? • How often does the system fail? • How long does audio failure last? • Can a loud clicking noise be heard in connection with the fault? • Is the system OK again after switching terminal 15 off and on? • What was shown on the main screen and in the assistance window? • Does the control display fail? • Is the display white or black or does it flicker in connection with the fault? • Can a status line still be seen? • What is shown after resetting the MOST bus (last menu, basic menu/start menu, BMW logo)? • Does the CD changer make a noise after audio failure? 33 Introduction to Advanced Body Electronics In addition, various factors that could also cause malfunctions in the system should be clarified: • What control units have already been replaced? • Did the fault symptom change after replacing control units? • Was the light intensity reduced for the control units? • Were the plug connections at the MOST control units checked? • Was another or new road DVD inserted? • What road DVD was used? • Was something retrofitted on the vehicle or a repair carried out? • To what CIP status (integration stage) does the vehicle correspond? • Were aftermarket parts retrofitted into any vehicle electrical systems? Based on the information provided by the customer and after examining any changes in the system it may be possible to determine faults already at this stage. Why are these statements important? Examples from visual applications: Creating Images The control display (CD) contains two control units, i.e. the CD gateway that establishes the connection to the other bus systems and the CD graphics stage that builds up the graphics in the control display. Not all images in the CD are created by the CD graphics stage. All basic menus, sub-menus and the status line are created by the graphics stage (blue). The map is presented by the navigation computer via RGB lines (red). Consequently: If only the map is not displayed but the rest, e.g. the on-board computer, is still visible and if other menus can still be selected via the controller, in all probability the fault will be in the area of the navigation system. Important: The navigation map can also be displayed on the left-hand side. Non-Digitized Area A road map DVD, on which an area is not completely digitized can cause the navigation screen to turn green. Self-Burnt DVDs A self-burnt or faults road map DVD can cause the navigation computer to crash. Also a defective computer can trigger a reset of the navigation system, indicating "Initialization running" in the control display. 34 Introduction to Advanced Body Electronics Telephone E65 The telephone AF is routed via the MOST bus in the form of light signals to the ASK. The light is converted in the ASK and the AF is output from the speakers by means of a hard¬ wired electrical signal. The microphone is connected via copper cables directly to the telephone control unit. Even if an SVS is installed, it does not have anything directly to do with hands-free tele¬ phone operation. SVS is activated when voice commands are executed. The cause of a fault in hands-free operation should be sought in the area of the microphone, telephone and ASK. If the telephone PIN is necessary after failure of the MOST bus, this indicates that the telephone control unit triggered a reset and in all probability the fault can be rectified by replacing the telephone control unit. If the MOST bus is blocked, a telephone conversation via the cordless keypad handset should still be possible provided the telephone itself is not defective. Audio The two models E60 and E65 differ considerably in the area of the audio systems. These design differences necessitate different assessment methods for the purpose of locating faults. The ASK is responsible for audio output on the E65. If the vehicle is equipped with a Top HiFi amplifier, the audio signal is sent in the form of a light signal from the audio source to the Top HiFi amplifier and forwarded to the speakers as an electrical signal. Some of the speakers are activated directly by the ASK and some by the Top HiFi amplifi¬ er (LOGIC 7). If the E65 is equipped with a HiFi amplifier, the sound information is transferred via a hard wire circuit to the amplifier. In connection with the Top HiFi system on the E60, all sound signals are routed from the multi-audio system controller/car communication computer in the form of light signals to the Top HiFi amplifier. No sound signals are transmitted along fibre-optic cables in connection with the stereo and HiFi systems. The multi-audio system controller/car communication computer itself is responsible for the control of the speakers. 35 Introduction to Advanced Body Electronics E60 MOST Bus Diagnosis The MOST network uses a ring bus for data communication between the various mod¬ ules. Signal transmission is by means of a fiber-optic cable. Data transmission on the ring bus takes place in one direction only. On the the MOST ring, messages can only be transmitted provided the bus ring complete and fully functional. If for example the power supply or the diode of a control module is defective, the MOST bus in non-operational and no communication is able to take place. Exceptions are the gateway control module (CCC or MASK) and the HUD control module. CCC/MASK E60 series vehicles are fitted with either the CCC or the MASK. Either of these control modules are the interface between the MOST bus and the K-CAN. To diagnose the CCC or MASK: • CCC (Car Communication Computer) all the control modules with the abbreviation CCC must be selected (e.g. CCC-GW). • MASK (Multi Audio System Controller) all the control modules the the abbreviation MASK must be selected (e.g. MASK-GW). Diagnosis Excessive Temperature If a control module becomes too hot, this control module switches off for up to 10 min¬ utes. This switches the ENTIRE MOST bus down for 10 minutes. After the control module cools down it (and the MOST bus) is functional again. If this fault, “Deactivation excess temperature”, is stored in the CCC (or MASK) and any of the other MOST control modules there are two possibilities: • If the fault is ONLY in the CCC (MASK), then this module is responsible for the MOST bus shut down. • If the fault is stored in the CCC (MASK) and one or more other control modules on the MOST bus, the most likely cause of MOST bus failure is the other control mod¬ ule. However, this does not rule out the possibility that the CCC (MASK) is also defective. Control Module Resets Using the DISplus or GT1 a Test Plan may be run to check number of control module resets for each control module on the MOST bus. A control module with 0 (zero) resets has performed no reset, is not installed in the vehi¬ cle, or can not be found with the diagnostic eguipment. The control module with the highest number of resets is the most probable cause of a fault with the MOST bus. 36 Introduction to Advanced Body Electronics Below is an example of a readout from the DISplus or GT1: Head-Up Display 15 CD Changer 0 Headset Interface 0 Amplifier 0 Video Module 0 Telephone 0 Satellite Radio 0 Nav System Japan 0 MASK (or CCC) 15 Note: Resets at a rate of less than 10 may be normal for a control module. When the number of resets is less than 10, this is only an indication on the pos¬ sible cause of a fault. The control module should generally NOT be replaced with less than 10 resets. MOST Configuration On the E60, certain control units are always arranged in the same order. Other control units, on the other hand, can be connected in a different sequence. Same Sequence Depending on the equipment configuration, the multi-audio system controller/car com¬ munication computer is always followed by the CDC, HUD and then the MOST bus ter¬ minal. Different Sequence The sequence can change as from the MOST bus terminal. Possible control units include: - Top HiFi amplifier - Telephone - Video module From the MOST bus terminal, the fibre-optic cable is routed back via the flash plug to the multi-audio system controller/car communication computer. 37 Introduction to Advanced Body Electronics Store Configuration On the E60, the sequence of control units in the MOST system network is identical in the front area of the vehicle. All control units located in the luggage compartment can be connected to the MOST bus terminal in any arbitrary order so that the sequence of the control units can change. Diagnosis on the MOST bus is only possible over a known sequence of control units in the MOST. When storing the MOST ring configuration, the control units are written in their installed sequence to a registration file. It is first necessary to check whether com¬ munication on the MOST bus is possible (stability check). The configuration is automatically restored after replacing or retrofitting a control unit in the MOST system network. This takes place after programming/encoding with CIP so that the control unit sequence is up-to-date. The "Store configuration" function is not activated automatically when the control units sequence is changed manually in the area of the luggage compartment (e.g. accident damage repair). E60 MOST control unit sequence K-CAN ccc M-ASK FS CDC HUD 04219.03 TEL TOP-HIFI VM 38 Introduction to Advanced Body Electronics Ring Break Diagnosis Ring break diagnosis is already known from the E65. During ring break diagnosis on the E65, the voltage supply is interrupted directly at the battery. Contrary to the E65, restart of the MOST users on the E60 is realized via "Transport mode." The following relays are switched off: • Relay 1 MPM • Terminal 30g These relays supply voltage to all control units in the MOST system network. On activat¬ ing transport mode, the relays are switched off and the voltage supply interrupted. After the relays have been switched on again and the control units started up, the multi¬ audio system controller/car communication computer can detect the control units that still have communication capabilities and evaluate the results. Consequently, the BMW diag¬ nosis system specifies a nodal point that provides an indication of the interruption on the MOST bus. The functional description in the BMW diagnosis system provides detailed information on determining the nodal position on the MOST bus. Stability Check On the E60, the antenna tuner and the audio system controller are located in one unit. The radio is still operable in the stereo and in the HiFi system in the event of a communi¬ cation fault in the MOST system network. The stability check module was introduced for the purpose of checking the MOST bus in such cases. Effective operation of the MOST bus on the E60 can be checked with the stability check function. MOST Control Unit Supply The "MOST control unit supply" module makes available schematic circuit diagrams and information on the power supply of the MOST control units so that specific information is quickly available as required. 39 Introduction to Advanced Body Electronics Repair of the MOST Fiber-Optic Cables The MOST bus may only be repaired (spliced) once between 2 control units, otherwise the attenuation may become too much and disrupt communication. Attenuation in the Fiber-optic line increases as the distance between controllers increases. This diagram describes the approximate length of the fiber optic cable from one controller to the next. Color Length Max. Attenuation ■ 1-1.5 -1.4dB ■ 1.5-2 -1.7dB ■ 2.5-3 -2.4dB 5-5.5 -4.5dB The chart above provides the maximum attenuation values based on the cable length. The MOST bus may only be repaired using the prescribed special tool (crimping pliers) and special connectors. 40 Introduction to Advanced Body Electronics Workshop Exercise - E65 MOST (Ring Break Diagnosis) Using an E65/E66 disconnect an instructor designated MOST bus component and perform complete quick test. What is observed from the quick test results? Access the “Ring Break” test plan in the diagnosis program. (Note: There are 2 paths to access the ring break diagnostics). Follow the on-screen prompts. How can it be determined whether or not there is an existing ring break? What are the results of the ring break test? (What nodal position is indicated?) What does this nodal position indicate? What are some possible causes of a “ring break” fault? Restore MOST bus connection and clear all faults. 41 Introduction to Advanced Body Electronics Workshop Exercise - E65 MOST (Luminous Power Reduction) Using the instructor supplied “attenuation tool”, dial in the appropriate amount of attenuation as to cause “crackling” in the audio system. Go to “luminous power reduction” test (a.k.a “test- drop in light output”). Perform test and follow on-screen instructions. What is the “luminous power reduction” test used for? (And when should it be used?) Which component (if any) exhibited a problem during the test? What does this indicate? Using the “control unit functions” menu and access the affected module. Perform the luminous power reduction test via the component activation menu. What occurs during the test? What does this indicate? 42 Introduction to Advanced Body Electronics Workshop Exercise - E65 MOST (Attenuation Testing) Using the OPPS/OPS tester, perform an attenuation test on an instructor designated component/system. Follow on-screen prompts. What is tool# 663124 used for? During the 1st calibration step (using 663124), what is the observed attenuation reading? What is the allowable attenuation for this step? Note: Observe extreme caution when installing or removing tool # 663125. Permanent damage can result to the test cables, which would invalidate attenuation readings. What is the observed attenuation reading of the MOST control module being tested? What is the specification for the attenuation test for the MOST control module? Why is it necessary to reset the OPPS/OPS tester? Perform attenuation test on the “optical wave guide”. Follow on-screen prompts. What is the observed attenuation reading of the “optical wave guide” being tested? What is the specification for the attenuation test for the “optical wave guide”? 43 Introduction to Advanced Body Electronics Workshop Exercise - MOST Bus (E60,E63 and E64) Using an instructor designated vehicle, locate the MOST splice point in the rear of the vehicle. Determine the order of the MOST ring manually and record below: 11 “ ccc M-ASK FS sV List the diagnosis path to access MOST configuration: As per the instructors directions, manually re-configure the MOST bus by re-order¬ ing selected components using the MOST bus splice point. Check the re-configured MOST bus by access the MOST configuration test module in diagnosis. Why is this test module important and when would it be used? 44 Introduction to Advanced Body Electronics Workshop Exercise - MOST Bus (E60,E63 and E64) After completing the MOST configuration test module, record the new (re-ordered) MOST bus configuration below: e; (M219.CC Restore MOST bus to original configuration and re-check system. Locate the fiber optic jumper harness. Where is the fiber optic jumper located? 45 Introduction to Advanced Body Electronics byte flight Introduction The permanently increasing complexity of in-car electronics and the rapidly growing amount of sen¬ sors, actuators and electronic control units, places higher demands on high-speed data communica¬ tion protocols. Safety critical systems need guick “thinking” proto¬ cols with fault tolerant behavior. The need for on¬ board diagnostics calls for flexible use of bandwidth and an ever-increasing number of functions. None of the communication solutions available on the market until now have been able to fulfill all these demands. To solve these problems, BMW together with sever¬ al semiconductor companies have developed byte- flight a new protocol for safety-critical applications in automotive vehicles. D-Bus K-CAN f I ZGM PT-CAN cn cn '--j ic jri u O' o mk o byte flight The byteflight is the bus system used exclusively for the ISIS system. Design The Intelligent Safety Integration System (ISIS) consists, depending on equipment level, of up to 11 satellites (control units), the Safety Information Module (SIM) and the Central Gateway module (ZGM). Seven of the eleven satellites contain crash detection sensors. In the event of an accident, the necessary restraint systems have to be activated within a fraction of a second in order to provide the maximum amount of protection for the vehi¬ cle's occupants. The system also has to ensure that the restraint systems are not deployed accidentally. In order to ensure that the ISIS meets the requirements placed upon it, large volumes of data have to be exchanged between the control units. This is achieved by means of an extremely high data transmission rate. The data is exchanged via a bus system. In order to protect the signals traveling along the bus system from interference caused by electrical or magnetic fields, the ISIS system does not use copper bus wires but optical fibers. 46 Introduction to Advanced Body Electronics The layout of the ISIS takes the form of a star pattern. The Safety Information Module (SIM) is at the center of the system. Arranged radially around it are the satellite modules. Each of the eleven satellites is connected to the SIM by a fibre-optic cable. Each of the satellites contains a transmitter/receiver module. The SIM contains twelve transmitter and receiver modules. All information from each of the satellites is made available to every other satellite by the SIM. Each individual fibre- optic cable in the byteflight bus system is used for bi-directional data transmission. Function Transmitter/Receiver Module (SE) The transmitter/receiver module is a module that can convert electrical signals into optical signals and transmit them via optical fibers. Every satellite has an electrical-optical trans¬ mitter/ receiver module. Intelligent Star Coupler The transmitter/receiver modules are connected individually via the byteflight to the Intelligent Star Coupler in the SIM. The SIM also contains a transmitter/receiver module for each satellite. All information transmitted across the byteflight is in the form of data telegrams sent by means of light pulses. The transmitter/ receiver modules in the SIM receive the light puls¬ es from the various satellites. The Intelligent Star Coupler sends the data telegrams to all satellites. Data transmission is possible in both directions. 47 Introduction to Advanced Body Electronics 3S The transmitter/receiver (SE) module contains the LED for the driver circuit and the receiver amplifier for converting the optical signals into digital signals. It also has an inte¬ gral transmission guality monitoring circuit. If one of the following faults occurs on one of the fiber-optic cables, the satel¬ lite concerned is shut down: • No optical signal received over a pre-defined period. • Transmitter diode sends a continuous light signal. • Attenuation on the fiber-optic cable too great. The permissible degree of attenuation is stored within the system. If the attenuation exceeds the specified maximum level, one of the following faults may be the cause: • Kinking in the fiber-optic cable. • Compression of the fiber-optic cable. • Stretching of the fiber-optic cable. • Broken fiber-optic cable. • Damaged fiber-optic cable. 48 Introduction to Advanced Body Electronics Data Transmission The ISIS has a number of sensors positioned at strategic points throughout the vehicle. They are located in the satellites that are connected to the SIM via the byteflight. All sen¬ sors are scanned continuously and the data distributed to all satellites. Airbag Satellit mit Sensor Airbag Satellit mit Sensor Airbag O O Airbag O Satellit mit □ □ □ 0 Satellit mit Sensor Diagnosis Diagnosis of the byteflight is carried out using the Diagnosis Program. Since the byte- flight is a star structure and not a continuous ring like the MOST there is a test module “Data transmission to the satellites” that can check communication between each satel¬ lite and the SIM module. Any satellite that does not respond must then be checked individually using a separate Test Module. Repairs to the byteflight fiber-optic cable are not permitted. However, complete cables between the SIM and the affected satellites may be replaced. 49 Introduction to Advanced Body Electronics Controller Area Network (CAN Bus) Introduction The CAN bus is a serial communications bus in which all connected control units can send as well as receive information. Data exchanges over a CAN operate at a rate of 100 to 500Kbps. The CAN protocol was originally developed by Robert Bosch GMbH and the Intel corpo¬ ration in 1988 for use in the automotive electronics industry to provide a standardized, reliable and cost-effective communications bus. The CAN bus was originally introduced on BMW automobiles in 1992 740i/iL as a data link between the DME and AGS control units. E65 K-CAN Introduction For the E65, the functions that were incorporated within the main bodyshell electrical system on the E38 have been distributed among a number of separate control units. Those control units and various new control units are connected to the K-CAN. The K-CAN is a new development and is subdivided into two sections, the K-CAN System and the K-CAN Peripherals. Examples of new control units and functions on the K-CAN are the Car Access System (CAS), the Centre Console Control Center module (BZM), the Rear Centre Console Control Center module (BZMF) and the Power Module (PM). K-CAN System/Peripherals The subdivision of the K-CAN into the sections "SYSTEM" and "PERIPHERALS" relieves the load on the bus because the number of vehicle components (control units/modules) is divided between two "independent" bus systems. 50 Introduction to Advanced Body Electronics Advantages of two K-CAN Busses The advantages of two K-CAN busses are as follows: • In a crash, it is possible that components could fail as a result of a short circuit on the K-CAN. The K-CAN Peripherals covers such at-risk areas. If the K-CAN Peripherals were to fail, the K-CAN System would still remain functional. • Addition of new vehicle components to either bus is possible at any time. (Maximum 40 control units per bus) • Low data load on the bus system from bus users due to division into two sections. • Greater reliability. K-CAN P K-CAN S 51 Introduction to Advanced Body Electronics Voltage Level on the K-CAN. If the CAN High voltage level changes from low to high, this represents a logical 1. If the voltage level changes back to low, this represents a logical 0. The voltage level on the CAN is in the range of 1V to 5V. Note: The voltage can alter as a result of a defective terminal resistor, for exam¬ ple. This has an effect on the CAN system. Communication between bus nodes no longer functions properly. Terminal Resistor An electrical conductor through which current passes always has an ohmic, an inductive and a capacitive impedance. When data is transmitted from point "A" to point "B" over a CAN line, the total sum of that impedance has an effect on the transmission of that data. The higher the transmission freguency, the greater the effect of the inductive and capaci¬ tive impedance. The result of this can be that when the signal reaches the end of the data transmission line, it is unidentifiable. For that reason, the data line is "modified" by termi¬ nal resistors so as to preserve the original signal. The inductive impedance is produced by phenomena such as the coil effect of the wire. The capacitive impedance for example is produced by the effect of routing the wire paral¬ lel to the vehicle body. The terminal resistors on a bus system vary. They are generally dependent on the following parameters: • Freguency of data transmission on the bus system. • Inductive/capacitive load on the transmission channel. • Length of the data transmission cable (The longer the cable is, the greater is the inductive component). 52 Introduction to Advanced Body Electronics The control units are categorized either as basic control units or other control units. Categorization is performed on the basis of the impedance level. Basic control units are those which always have to be fitted in the car regardless of eguipment level or market. Other control units are those that are dependent on the options fitted. The terminal resistor values for the K-CAN system are 820 Ohm for “Basic” controllers and 12K Ohms for all other control units. For the E65 the Basic controllers are: K-CAN S: LM, IHKA, CAS, CD, ZGM, KOMBI. K-CAN P: CAS, TMFAT, TMBFT, HKL The resistors are located inside of the control units. Wake-Up on the K-CAN The control units on the K-CAN network are "awakened" via the bus. For that reason, it has been possible to dispense with the previous function of terminal 15 as wake-up line. The wake-up message is passed directly to the control unit output stage by the CAS module receiver. The output stage switches terminal 30 on and the unit is woken up. 53 Introduction to Advanced Body Electronics PT (Powertrain) CAN Introduction The PT CAN is the fastest CAN bus in the E65. It is an existing bus system. PT CAN stands for powertrain CAN. It links all control units/modules associated with the power- train. All the bus nodes are connected in parallel with one another. In contrast with the previous bus, (two-core twisted pair) it now has three wires. The third wire of the bus cable is used as the wake-up line and has nothing to do with the actual CAN bus func¬ tion. Voltage Level on the PT CAN When the bus is inactive, the bus high and low levels are at 2.5 V. When the bus becomes active, the CAN Low voltage level changes to low (1.5 V) and the CAN High level changes to high (4 V), thus representing logical 1. PT CAN Terminal Resistors The PT CAN uses two terminal resistors to establish the correct inductive and capacitive impedance in the communication lines. Two 120 Ohm resistors are located in the wire har¬ ness (no longer in the control units as on pre¬ vious systems). The resistors are located: • Ahead of the right front wheel. (Behind bumper) • Below the rear seat. The resistance is measured by connecting the appropriate adapter to any of the modules on the PT-CAN and measuring resistance between CAN-H and CAN-L. The measured resistance should be close to 60 Ohms. v Wake Up PT-CAN 54 Introduction to Advanced Body Electronics Failsafe Characteristics If the PT CAN goes into emergency mode it is no longer available for the engine control system. However, it can still provide communication between the other bus nodes even if: • One of the CAN leads (cores) is broken- one of the CAN leads (cores) is shorting to ground. • One of the CAN leads (cores) is shorting to the power supply B+. "Wake-up" Lead in PT CAN Network The PT CAN for the E65 is now a three wire CAN, the third wire is a hard wire KL-15 sig¬ nal used to wake up the powertrain control units. The "wake-up" lead has nothing to do with the actual PT CAN function. A wake-up telegram is still transmitted by the CAS via the ZGM - PT-CAN as a CAN message. Notes: 55 Introduction to Advanced Body Electronics Diagnosis Bus Introduction The aim of diagnosis is to enable a Technician to reliably identify a defective component. By the use of appropriate hardware and monitoring software, the microprocessor of a control unit, for example, is able to detect faults in the control unit and its peripherals. OBD scan tools 10.400 Bit/s CAS SMFA TMFAT TM FATH SMFAH HKL TM BFTH SM8FH PM AHM PDC RDC CIM LM OWA IHKA K-CAN P K-CAN S MOST byteflight PT-CAN Faults identified are stored in the fault memory and can be read out using the Diagnosis Program. Data transfer between the vehicle and the diagnosis tool takes place via the Diagnosis bus (D bus). The new features of the diagnosis bus are: • Faster data transmission speed of 115 kBd. • Central diagnosis access point (OBD connector). • Single diagnostic cable (TxD II) for the entire vehicle. • Omission of the TxDI cable. • Access to diagnosis functions reguires “Authorization”. • Diagnosis protocol "KWP 2000" (Keyword Protocol 2000). • Standardized diagnosis structure for all control units. 56 Introduction to Advanced Body Electronics Diagnosis Concept The "BMW Fast" (BMW fast access for service and testing) diagnosis concept introduced on the E65 is applied. This concept is based on the "Keyword Protocol 2000" (KWP 2000 ) diagnosis protocol defined as part of the ISO 14230 standard. Diagnosis communication takes place entirely on the basis of a transport protocol on the CAN bus. The Diagnosis bus is connected to the Central Gateway Module. All bus systems apart from the MOST bus are connected to the Central Gateway Module (ZGM). Vehicle Diagnosis Access Point The diagnosis tool is connected to the vehicle by means of the diagnosis connector OBD ( On-Board Diagnosis ). The connector is located behind a small cover in the drivers side kick panel trim. There is a black plastic cap that bridges KL-30 to the D-bus when the connector is not being used. This cap must be removed before installing the diagno¬ sis cable. TheTxD lead is located in pin 7 of the OBD socket and is connected directly to the ZGM. The ZGM detects by means of the data trans-mission speed whether a BMW diagnosis tool (DISplus, GT-1) or an aftermarket scanner is connected. The DME allows access to different data depending on the diagnosis tool connected. Note: When using an OBD scan tool for diagnosis, the transmission speed is 10.4 KBit/s. 57 Introduction to Advanced Body Electronics Workshop Exercise - PT-CAN Using an instructor designated vehicle, access the DME (ECM) and connect the appropriate breakout box and test cables. Using the Oscilloscope, obtain a pattern of the CAN High signal. What is the voltage of the CAN High signal? And what else can be observed of the CAN High signal? What is the wire color for CAN High? _ Record you oscilloscope setting and connections below. Voltage_ Freguency _ Connections: MFK 1 or 2 Describe positive and negative connections below: Using the Oscilloscope, obtain a pattern of the CAN Low signal. What is the voltage of the CAN Low signal? And what else can be observed of the CAN Low signal? What is the wire color for CAN Low? Record you oscilloscope setting and connections below. Voltage _ Frequency _ Connections: MFK 1 or 2 Describe positive and negative connections below: 58 Introduction to Advanced Body Electronics Workshop Exercise - PT-CAN Using the DISplus or GT-1 (with MIB), display the CAN High and CAN low signal together. What can be observed regarding these two signals? Using the multi-meter functions of the DISplus/GT-1, measure the resistance between CAN High and CAN Low. What is the total resistance between CAN High and CAN Low? What causes the resistance readings obtained? Where are the PT-CAN terminal resistors located in this vehicle? What is the resistance value of the PT-CAN terminal resistors? What occurs when CAN High is grounded? What occurs when CAN High is grounded? 59 Introduction to Advanced Body Electronics Workshop Exercise - K-CAN Using an instructor designated vehicle, access the K-CAN circuit and display pattern on oscilloscope. What is the voltage of the K-CAN (High and Low)? What are the major differences between the K-CAN and PT-CAN scope patterns? What occurs if there is a malfunction of the K-CAN Low circuit? (i.e. open/grounded) What occurs if there is a malfunction of the K-CAN High circuit? (i.e. open/grounded) Measure the resistance between K-CAN High and K-CAN low. What is the total resistance between K-CAN High and K-CAN Low? Where are the K-CAN terminal resistors located? What are the ohmic values of these resistors? 60 Introduction to Advanced Body Electronics Classroom Exercise - Review Questions Fill in the component location below: A. _ B. _ C. _ D. _ E._ In the E65, which modules perform the task of “Gateway”? What are some of the handling precautions when working with fiber-optic cables? 61 Introduction to Advanced Body Electronics 4. What is the difference between the fiber-optic connector of a MOST component and a byteflight component? 5. What is the difference between the D-Bus of the E65 and other BMW models? 6. How many terminal resistors are located in the PT-CAN? Where are they located? What should the total resistance be on the PT-CAN? 7. During a diagnosis of the MOST bus on an E65, the technician finds a recorded fault in the SVS. The fault is “A control module does not switch off light”. Which control module is most likely the cause of this fault? And why? (explain answer) 8. When performing the “ring break” diagnosis test, battery voltage must be interrupted to MOST bus control units. What is the difference between the methods of disconnecting voltage on the E65 versus the E60? 62 Introduction to Advanced Body Electronics