Communication bus systems

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1 Communication bus systems Communication bus systems Course code: CS03 Student training manual Suzuki Online Training

2 Foreword Networks for data communication, also known as bus systems or protocols, are widely used in today s motor vehicles. Various components such as sensors, actuators or computers nodes are connected to each other via a single channel which can consists of one or several wires. A wealth of data is exchanged via this channel. In this training manual, we will study fundamentals of networking systems used in Suzuki vehicles. Smart manuals Some sections of this training manual contain videos with detailed information on the topics you are studying. If you are studying this training manual on a PC, look out for the green play video symbol on any photo or picture in this manual, click on the green button to watch a video providing you with detailed information on that topic. Note: Internet connection required. This document is intended solely for training purposes only. All vehicle repairs and adjustments must be carried out according to the procedures stipulated in current service manuals and technical bulletins. Suzuki Technician curriculum This training manual is part of the Non Suzuki Technician to Suzuki Technician curriculum. The curriculum consists of the following modules: 1. GE01 Suzuki Introduction 2. GE02 Electrical / Electronics 3. GE03 Diagnostics 4. EN02 Engine Mechanical part I 5. EN03 Engine Mechanical part II 6. EN04 Engine Mechanical part III 7. EN05 Engine Auxiliary systems 8. DS01 Driveshaft/Axle 9. DS02 Driveshaft/Axle transfer case 10. BR02 Brake control systems 11. Manual transmission / transaxle 12. CS02 Control system / body electrical 13. CS03 Communication / bus systems You are currently studying CS03 Control systems/body electrical. This module consists of the following courses: Communication bus systems Communication bus systems practical act ivies CS02 Control Systems I Body Electrical 2

3 Table of contents Topic Bus systems 4 Types of serial communication 4 Classification of bus systems 5 Communication network topology 5 CAN 7 Data transmission 7 Voltage levels 8 CAN message format 8 Controlling bus access 9 Filtering of incoming data messages 10 CAN network hardware 11 Data transmission system 11 Reflection free termination 11 Network nodes 12 Suzuki CAN communication topology 13 LIN 21 Data transmission in the LIN bus 22 LIN protocol 22 Application of LIN bus in Suzuki vehicles 23 UART communication bus 24 Application of UART in Suzuki vehicles 24 Serial Communication 25 Application of serial communication Suzuki vehicles 26 Page Topic Diagnosis 27 DLC 27 Measurement options 27 List of abbreviations 30 Page CS02 Control Systems I Body Electrical 3

4 1. Bus systems Communication for each control module and device is established through continuous input/output of ON/OFF digital signals with various data items being managed in parallel. Transmitting/receiving this data is called serial communication interface. The following protocols have been adopted for incar communication systems on Suzuki vehicles. 1.1 Types of serial communication CAN The CAN system is a twisted pair of two communication lines (CAN High and CAN Low) connected between electronic control modules. Data obtained by a specific control module can be shared with other control modules connected to the CAN network. In some Suzuki models for example, the keyless start control module, BCM, ECM, TCM (CVT model), combination meter, P/S control module, HVAC control module, ESP control module, 4WD control module (4WD model), SDM, steering angle sensor, and rain / light sensor are transmitted/received through CAN. Types of serial communication interface such as UART, CAN and LIN protocols (communication standards) have been adopted for in-car communication system in Suzuki vehicles. UART UART is a type of "asynchronous receiver/transmitter", a piece of computer hardware that translates data between parallel and serial forms. UART is used for example in the communication from keyless start control module to steering lock unit. K-line The K-line bus system consists of a single wire. It is not used for communication between control modules by exclusively for diagnosing an individual control module. In modern vehicles, the K-line bus system is increasingly being replaced by the CAN bus system. LIN LIN is a single wire communication system used for communication between sensors and actuators in the body electronics area. LIN is used for example in the communication from keyless start control module to each front power window motor and power window master switch, for communication from combination meter to parking sensor system control module, and for communication from HVAC control module to auto A/C panel. CS02 Control Systems I Body Electrical 4

5 1.2 Classification of bus systems 1.3 Communication network topology Class Transfer rates Applications Representative A B C Low data rates, up to 10 kbit/s Average data rates, up to 125 kbit/s High data rates, up to 1 Mbit/s Actuator & sensor networking Complex mechanisms for error handling, control unit networking Real time requirements, control unit networking in the powertrain functions LIN Low speed CAN High speed CAN Control modules, some intelligent sensors and actuators are connected to each other using communication networks. Figure 1 shows a typical network topology. The control modules connected to the communication network vary according to vehicle s equipment level. In most Suzuki vehicles, the network topology consists of mainly the Class C (High Speed CAN) and the Class A (LIN) bus systems. The UART serial communication and K-line can also be found in some models. C+ Extremely high, up to 10 Mbit/s Real time requirements, control unit networking in the powertrain functions FlexRay D Extremely high, >10 Mbit/s Control unit networking in the telematics and multimedia functions MOST CS02 Control Systems I Body Electrical 5

6 Communication network topology DLC Power Steering ECM CVT Parking sensor control module Combination meter BCM ABS/ESP Junction Connector Junction Connector Steering lock Keyless start control Steering angle sensor SDM Rain/Light sensor HVAC Keyless entry receiver CAN Front Power window motors Front Power window master switch A/C control panel UART LIN Figure 1: Network topology (Suzuki Kizashi A6B424 2WD CVT model) CS02 Control Systems I Body Electrical 6

7 2. CAN communication CAN communication system is a serial communication system for transmitting a multiple data items (values from sensors, control data and control signals) as ON-OFF digital signals through communication lines. This system uses two lines (CAN High and CAN Low) for the communication circuit so as to maintain high reliability even when used for high-speed serial communication. 2.1 CAN overview Data transmission To communicate, the CAN bus uses two states dominant and recessive, with which the information bits are transmitted. The dominant state represents 0 and the recessive state represents 1. CAN has the following advantages: 1 a) Less wiring is used for communication between electronic control modules which results in reduced production costs. b) Sensor signals can be used by multiple electronic control modules without the need for additional wiring or sensors. c) Improved reliability and functional reliability due to fewer connectors. d) Simple connection of system components to a bus. 0 Figure 2: CAN data signal 0 Dominant 1 Recessive CAN protocols The CAN bus system has four different protocol formats, each suitable for a specific application. a) Data transmission protocol b) Data request protocol c) Fault message protocol d) Overload message protocol Data is transmitted in the CAN bus system using two-wire harness. The first wire is called CAN_H and the other wire is called CAN_L. The two wire system facilitates a symmetrical data transfer in which the bits are transferred via both bus lines using different voltages. This reduces sensitivity to common-node interference, since interference affects both lines and can be filtered out. The wires are twisted together so that any interference affects both CAN_H and CAN_L equally. CS02 Control Systems I Body Electrical 7

When CAN High signal is 3.5 V and CAN Low signal is 1.5 V (that is, when the difference between High voltage and Low voltage is about 2 V), signal is judged as ON.

8 When CAN High signal is 3.5 V and CAN Low signal is 1.5 V (that is, when the difference between High voltage and Low voltage is about 2 V), signal is judged as ON. For this reason, the signal waveform between CAN High and CAN Low signals is symmetrical with respect to 2.5 V level. CAN communication fails when the symmetrical signal form collapses CAN message format A B C D E F G H 1 Figure 3: Data transmission in a CAN line 0 Idle 1* 12* 6* 0.64* 16* 2* 7* 3* Idle Data frame Voltage levels Message frame The CAN High (CAN_H) and CAN Low (CAN_L) use different voltage levels to transfer dominant and recessive states. with 2.5 V as the reference level for both CAN High signal and CAN Low signal. The range of CAN High signal is from 2.5 V to about 3.5 V and that of CAN Low signal is from 2.5 V to about 1.5 V. When both are at 2.5 V, signal is judged as OFF. Figure 4: CAN message format [A] Start of message [B] Arbitration field [C] Control field [D] Data field [E] CRC field [F] ACK field [G] End of message [H] Inter-message space CS02 Control Systems I Body Electrical 8

9 For data transfer on the CAN bus, a message frame is created. The message frame contains the information to be transmitted arranged in a specific sequence. The message transmission sequence is as illustrated in figure 4 and described as follows: A) Start frame The bus state is recessive (1) in the idle state. The start of the frame is represented by a dominant bit and indicates the start of data transmission. B) Arbitration field The arbitration field is made up of 12 bits (11 bit identifier followed by SRR 1 (substitute remote request ) bit). Since only one message can be transmitted using the bus at a time, the arbitration field is used to determine the priority of data to be transmitted. C) Control field The control field contains the code indicating the number of data bytes in the data field D) Data field The data field contains the actual message being sent e.g. engine coolant temperature. This message consists of between 0 and 8 Bytes. E) CRC field The CRC (Cyclic Redundancy Check) contains a checksum for detecting possible transmission interference. F) ACK field The ACK (acknowledgement) field contains the acknowledgement signals with which the receivers indicate the error-free receipt of a message. Only correct receipt is confirmed and this signals to the sender that no malfunction occurred during data transfer. G) End of message The end of message contains 7 recessive bits and marks the end of the data transmission. H) Inter-message space This frame consists of 3 bits is used to separate messages being sent in the bus system Controlling bus access If the bus is in the recessive state (unoccupied), messages are available for sending. Each of the control modules connected to the bus can begin sending a message. A message begins with a dominant bit (start of message bit), followed by the identifier. When several control modules begin sending a message simultaneously, the system resolves the conflict by employing arbitration. The message with the highest priority (lowest binary value of the identifier) is allowed first access to the bus. Each station outputs the identifier of its message onto the bus bit by bit, with the most significant bit first. CS02 Control Systems I Body Electrical 9

10 Figure 5 shows an example of messages being sent simultaneously from the HVAC, CVT, ABS/ESP control modules. The following start transmitting the following messages at the same time. The HVAC and CVT data messages lose bus access allowing only the data message from the ABS/ESP to use access the bus first. HVAC Blower fan step signal ABS/ESP Torque up/down request signal CVT Fluid temperature signal HVAC Filtering of incoming data messages Each message sent by any of the control modules connected to the CAN bus have a unique marker or identifier. The identifier classifies the content of the message e.g. engine temperature. Each control module is able to broadcast a message to all other stations. These station s read only those messages whose identifiers are stored in their acceptance list. When a control module receives a broadcast message, it whether or not it needs the message or not. If it the control module receives messages that it does not need, it will ignore the message. On the other hand, if a control module receives a message that needs, it will accept the message. Combination Meter ECM BCM TCM ABS/ ESP 1 0 Data accept Reception Provision Data Ignored Data accept Reception CVT 1 0 Reception Send message Reception Reception A B CAN_H Figure 5: Bit arbitration CAN_L [A] HVAC signal loses the arbitration [B] CVT signal loses the arbitration Figure 6: Addressing and message filtering Engine speed message sent by engine control module to CAN bus network CS02 Control Systems I Body Electrical 10

11 2.2 CAN network hardware Data transmission system Electronic control modules are connected to the CAN network in parallel as shown in figure 6. It is possible to connect at least 30 electronic control modules to the bus without the need for additional measures Reflection free termination Reflections of the electrical signals at open ends of lines would interfere with communication. To dampen these reflections, the bus lines are terminated at each end with a resistor of 120Ω (shown in item 1 and 4 of figure 6). Alternately the control terminating resistors can be integrated in the control modules themselves. For example, in the Suzuki Kizashi, the terminating resistor are installed in the ECM and the Combination Meter. 1 4 CAN_H 5 5 CAN_L Figure 6: Structure of the CAN network [1] Combination meter [2] ABS control module [3] TCM control module [4] ECM [5] Terminating resistor CS02 Control Systems I Body Electrical 11

12 2.2.3 Network nodes The electronic control modules attached to the CAN system have network nodes. The network nodes have the application software, the CAN transceiver and the CAN controller. The CAN controller generates the bit stream for data communication from the binary data to be transmitted and forwards it to the transceiver on the TxD line. The Transceiver amplifies the signals, generates the voltage level required for differential data transfer and transmits the processed bit stream serially on the CAN bus lines. Incoming messages are processed by the transceiver and sent to the CAN controller on the RxD line. The microcontroller which runs the application program (Engine Control or ABS/ESP control etc.) controls the CAN controller, prepares the data to be sent and evaluates the data received. A data bit can either be ON (1) or OFF (0) There are 8 bits in 1 byte 256 different pieces of information can be transmitted using 8 bits (1 byte) Data is transmitted serially in the CAN bus system The CAN, LIN, K-line & UART have been employed in Suzuki vehicles. Two terminating resistors are installed in the CAN bus system. Each resistor has a resistance value of 120Ω. The two CAN bus wires are twisted to improve transmission reliability. The data message transmitted in the CAN_H wire is symmetrically sent in the CAN_L wire as well. Actuators Microcontroller Sensors CAN controller CAN RxD CAN TxD CAN transceiver CAN_H CAN_L Figure 7: Network nodes CS02 Control Systems I Body Electrical 12

13 2.3 Suzuki CAN communication topology In the following pages, we will look at how the CAN bus system is used in some Suzuki models. What messages are transmitted and received by what control modules in the network. Please refer to the vehicle relevant service manuals for details of models not mentioned in this training manual. 3.1 Suzuki Alto (AMF310) CAN bus system CS02 Control Systems I Body Electrical 13

3.1.2 Bus systems employed CAN (Class C (High speed)) 3.1.3

14 3.1.2 Bus systems employed CAN (Class C (High speed)) Transmitting and Receiving data table CS02 Control Systems I Body Electrical 14

15 Transmitting and Receiving data table (Continued) CS02 Control Systems I Body Electrical 15

3.2 Suzuki Swift (AZH414) CAN bus system 3.2.1 CAN

16 3.2 Suzuki Swift (AZH414) CAN bus system CAN System diagram CAN CS02 Control Systems I Body Electrical 16

17 3.2.2 Bus systems employed CAN (Class C (High speed)), UART, LIN Transmitting and Receiving data table CS02 Control Systems I Body Electrical 17

3.3 Suzuki Kizashi (A6B424) CAN bus system 3.3.1 CAN system diagram [A] CAN

18 3.3 Suzuki Kizashi (A6B424) CAN bus system CAN system diagram [A] CAN communication line [B] 4WD model [C] 2WD model CS02 Control Systems I Body Electrical 18

3.3.2 Bus systems employed CAN (Class C (High speed)), LIN, UART 3.3.3

19 3.3.2 Bus systems employed CAN (Class C (High speed)), LIN, UART Transmitting and Receiving data table CS02 Control Systems I Body Electrical 19

20 Transmit (T): When 2 controllers start transmitting at the same time, the controller that is transmitting the information with the higher priority obtains the transmission permission and all other controllers enter the receiving mode. Receive (R): All data that is transmitted from the controllers is shared on the CAN communication line. The controllers receive only the information that they require from this data, which they can use in their control. Note: The ECM calculates the vehicle speed based on the wheel speed information that is transmitted from the ABS control module. The ECM then transmits the vehicle speed information to other control modules via the CAN bus. CS02 Control Systems I Body Electrical 20

21 3. LIN 3.1 Overview The increasing use of mechatronic systems in the motor vehicle gave rise to the idea of designing a cost-effective bus system as an alternative to the low-speed CAN. The LIN bus is suitable for low data rates of up to 10 kbit/s and is typically limited to a maximum of 16 bus subscribers. These subscribers can be intelligent sensors, actuators or switches with additional hardware for the LIN bus interface. [1] Keyless start control module [2] Driver side power window motor [3] Passenger side power window motor [4] Power window master switch LIN communication signal A LIN data bus system is made up of a LIN master and LIN slaves and the data bus wire. Terminating resistors are not used in the LIN data bus system Figure 9: LIN signal 4 LIN bus Figure 8: LIN bus with master and slave nodes (Suzuki Kizashi power window system shown) CS02 Control Systems I Body Electrical 21

22 3.1.2 LIN master The LIN master has information on the time sequence of all the data to be transmitted in the LIN bus. The LIN master carries out the following tasks: The software of the LIN master features a cycle which determines when and how often what messages are transmitted on the LIN data bus. It checks the speed at which data is transmitted in the LIN bus system. It performs conversion of the data transmitted. It performs diagnosis of the LIN slaves LIN slaves LIN slaves include sensors that evaluate measured values and send information to the LIN master. Transmission takes place in the form of digital signals via the LIN data bus system. 3.2 Data transmission in the LIN bus The LIN bus system is a single-wire line that is unshielded. The bus may adopt two logical states. The dominant level corresponds to the electrical voltage of approximately 0V and represents logical 0 state. The recessive level corresponds to battery voltage and represents logical 1 state LIN protocol Frame The information transferred on the LIN bus is embedded in a defined frame. A message initiated by the master always begins with a header. The message field (response) contains different information depending on the type of message. It also includes LIN actuators/modules. LIN actuators/modules receive commands from the LIN master. In the LIN bus system shown in figure 8, the power windows are controlled by ECUs build-in the power window motors. Operations of the power window ECU s are monitored by the keyless start control module. Figure 10: LIN message CS02 Control Systems I Body Electrical 22

23 Header The header is composed of the following: Synchronization break (at least 13 dominant bits) Synchronization field (consists of bit sequence ). This bit sequence causes all the connected LIN slaves to synchronize to the internal clock of the LIN master. Identifier field (8 bits) Identifier The third byte in the header is used as the identifier Data field The actual data follows the protocol header. The data have length of 1 to 8 data fields. A data field consists of 10 bits. Each data field is composed of a dominant start bit, a data byte (8 bits) and a recessive end bit. The start and end bits serve for post-synchronization and consequently for preventing transmission errors. 3.3 Application of LIN bus in Suzuki vehicles Suzuki Kizashi (A6B424) Keyless Start control Module Combination Meter Passenger side power window motor Driver side power window motor Master window switch (Driver s door) Parking sensor system control module HVAC control module Auto A/C control panel Suzuki Swift (AZH412/414) HVAC control module Auto A/C control panel CS02 Control Systems I Body Electrical 23

24 4. UART communication bus 4.1 Overview The microcontrollers that are used in control units have a simple interface called UART (Universal Asynchronous Receiver/Transmitter) on the chip, via which they can communicate with other devices. If no data is being exchanged, the bus level is 5V. When the start bit is transmitted (dominant level), the other station connected to the bus (receiver) is notified that a data transfer is starting. After the start bet has been received, the transmission of an 8 bit (1 byte) data word commences. The receiver that has synchronized itself to the start bit scans the data bus between each data bit and therefore assembles the transferred data byte. The eighth data bit is followed by the parity bit. This bit indicates whether the number of transmitted ones is odd or even. This allows the receiver to perform a simple check of possible errors. The sequence is completed by the stop bit. 4.2 Application of UART in Suzuki vehicles The UART communication bus is employed between the keyless start control module and the steering lock in the vehicles equipped with the keyless start system. Keyless Start Control Module Steering Lock Figure 11: UART interface transmission frame [1] Start bit [2] 8 data bits (1 byte) [3] Parity [4] Stop bit CS02 Control Systems I Body Electrical 24

25 5. Serial communication 5.1 Overview The data contained in one serial communication is called a frame. 1 frame is made up of multiple bytes. 1 byte is made up of a start bit, a data section and a stop bit. The data section is made up of 8 bits arranged in a series. Each bit is assigned to an information item for communication. By changing the bits that correspond to the information items between HI and LO, multiple information communications can be performed on a single communication line. When there are multiple communication destinations, multiple frames are generated in a single communication cycle. Note that the frame length varies depending on the communication. Figure 12: Serial communication message frame CS02 Control Systems I Body Electrical 25

26 5.2 Application of serial communication The network topology below shows an example of application of serial communication. Figure 13: Network topology (Swift RS model) CS02 Control Systems I Body Electrical 26

27 6. Diagnosis 6.1 DLC DLC is in compliance with SAE J1962 in its installation position, the shape of connector and pin assignment. OBD CAN High line and Low line (CAN line of ISO ) are used for SUZUKI scan tool (SUZUKI-SDT) or CAN communication OBD generic scan tool to communicate with ECM. In vehicles equipped with the K-line communication system. Pin number 7 or the DLC is used for communication with the relevant control module e.g. the 4WD control module of the Suzuki Grand Vitara uses the K-line system for diagnosis by the SDT. 6.2 Measurement options The following measurement options can be used for diagnosis of the CAN bus system: CAN data transmission test using the oscilloscope. Voltage measurements using a voltmeter. Terminating resistance measurements using ohmmeter Terminating resistance measurements The terminating resistor can be measured using a digital multimeter. Two 120Ω resistors are installed on either ends of the CAN bus. The total resistance of these terminating resistors is 60Ω as they are connected in parallel. Any resistance values other than 55Ω..65Ω indicate a fault in the CAN system. Figure 13: DTC (LHD model shown) [1] DLC location [2] B+ power supply [3] CAN_L line (Class C CAN) [4] ECM ground (signal ground) [5] Chassis ground [6] CAN_H line (Class C CAN) [7] SDT Voltage measurements The volt function of the digital multimeter can be used to measure the voltage levels of the CAN_H and CAN_L wires. Triggering of the digital multimeter takes place at the CAN reference level. With the ignition ON, the following voltages are measured: CS02 Control Systems I Body Electrical 27

28 CAN_H (DLC pin 6) = 2.5V CAN_L (DLC pin 14) = 2.5V If the voltages are as mentioned above, the data wires are in good order and the recessive voltage is present. The measurements does not, however provide information on whether data is being transmitted in the CAN bus system. In order to determine whether dominant data signals are present in the bus system, an oscilloscope must be used Measurement using the oscilloscope Reference voltage of both CAN High signal and CAN Low signal is 2.5 V. Waveform of CAN High signal is V and that of CAN Low signal is V. Figure 14: Normal waveform of CAN bus system [A] Ground level of each channel [B] Volt/div of each channel [C] Time/div of each channel [D] Waveform of channel 1 (CAN high signal) [E] Waveform of channel 2 (CAN low signal) CS02 Control Systems I Body Electrical 28

29 The LIN bus system was developed for use where the speeds of the CAN bus system are not necessary. The LIN bus system comprises of a LIN master and LIN slaves. The LIN slaves can include sensors or actuators or electronic control modules. A LIN message frame is made up of a message header and a message response. The UART bus system is used for communication between the keyless start system and the steering lock in the Kizashi and the Swift (AZH models). Measurements of the CAN bus system can be performed using an oscilloscope, voltmeter or ohmmeter. CS02 Control Systems I Body Electrical 29

30 Reference The following abbreviations can be used in this training manual A A/B ABDC ABS AC A/C A-ELR A/F ALR API APP A/T ATDC ATF AWD Air Bag After Bottom Dead Center Anti-lock Brake System Alternating Current Air Conditioning Automatic-Emergency Locking Retractor Air Fuel Ratio Automatic Locking Retractor American Petroleum Institute Accelerator Pedal Position Automatic Transmission, Automatic Transaxle After Top Dead Center Automatic Transmission Fluid, Automatic Transaxle Fluid All Wheel Drive B BARO Barometric Pressure BBDC Before Bottom Dead Center BCM Body electrical Control Module BTDC Before Top Dead Center B+ Battery Positive Voltage BB+ Battery Positive Voltage for Backup C CAN CKP CMP CO CO2 CPP CPU CVT D DC D/C DLC DOHC DOJ DOT DPF DRL DTC D/C Controller Area Network Crankshaft Position Camshaft Position Carbon Monoxide Carbon Dioxide Clutch Pedal Position Central Processing Unit Continuously Variable Transmission, Continuously Variable Transaxle Direct Current Driving Cycle Data Link Connector Double Over Head Camshaft Double Offset Joint Department of Transportation Diesel Particulate Filter Daytime Running Light Diagnostic Trouble Code (Diagnostic Code) Driving Cycle CS02 Control Systems I Body Electrical 30

31 E EBD ECM ECT ECU EEPROM EFE Heater EGR EGT ELR Electronic Brake Force Distribution Engine Control Module Engine Coolant Temperature Electronic Control Unit Electrically Erasable Programmable Read Only Memory Early Fuel Evaporation Heater Exhaust Gas Recirculation Exhaust Gas Temperature Emergency Locking Retractor ENG A-Stop Engine Auto Stop Start EPS Electronic Power Steering ESP Electronic Stability Program EVAP Evaporative Emission G GND GPS H HVAC HC HFC HI HO2S Ground Global Positioning System Heating, Ventilating and Air Conditioning Hydrocarbons Hydro Fluorocarbon High Heated Oxygen Sensor I IAC IAT IMT ISC ISO J JIS J/B J/C L L LCD LHD LIN LO LSPV M MAF MAP Max MFI Min MIL M/T Idle Air Control Intake Air Temperature Intake Manifold Tuning Idle Speed Control International Organization for Standardization Japanese Industrial Standards Junction Block Junction Connector Left Liquid Crystal Display LED Light Emitting Diode Left Hand Drive vehicle Local Interconnect Network Low Load Sensing Proportioning Valve Mass Air Flow Manifold Absolute Pressure Maximum Multiport Fuel Injection Minimum Malfunction Indicator Lamp ( CHECK ENGINE Light or SERVICE ENGINE SOON Light) Manual Transmission, Manual Transaxle CS02 Control Systems I Body Electrical 31

32 N NOx O OBD OCM OCV O/D OHC O2S Nitrogen Oxides On-Board Diagnostic system Occupant Classification Module Oil Control Valve Overdrive Over Head Camshaft Oxygen Sensor T TCC TCM TCSS TDC TP TPMS TWC Torque Converter Clutch Transmission Control Module Traction Control Support System Top Dead Center Throttle Position Tire Pressure Monitoring System Three-Way Catalytic converter P PCM PCV PM PNP P/S PSP R R RAM RHD ROM RPM S SAE SDM SDT SFI SI SOHC SRS Powertrain Control Module Positive Crankcase Ventilation Particulate Mater Park / Neutral Position Power Steering Power Steering Pressure Right Random Access Memory Right Hand Drive Vehicle Read Only Memory Engine Speed Society of Automotive Engineers Sensing and Diagnostic Module (Air Bag Controller, Air bag Control Module) Smart Diagnostic Tester Sequential Multiport Fuel Injection System International Single Over Head Camshaft Supplemental Restraint System U UART USB V VFD VIN VSS VVT W WU-OC WU-TWC Other 2WD 4WD Universal Asynchronous Receiver / Transmitter Universal Serial Bus Vacuum Fluorescent Display Vehicle Identification Number Vehicle Speed Sensor Variable Valve Timing Warm Up Oxidation Catalytic converter Warm Up Three-Way Catalytic converter 2-Wheel Drive 4-Wheel Drive Note: ESP is a trademark of Daimler AG DPF is a trademark of HJS Fahrzeugtechnik GmbH & Co KG and Suzuki is the trade mark licensee. CS02 Control Systems I Body Electrical 32

33 Well done, you have now completed the CS03 Communication bus systems online training course! Please take the online exam CS02 Control Systems I Body Electrical 33

SCI ISO-K CCD PCI CAN

SCI ISO-K CCD PCI CAN DCX Networks SCI (Serial Communication Interface): The system uses two wires; one to transmit and one to receive. ISO-K is the adaptation of the 9141 standards allowing two-way communication on a single