OBD-II - picprojects
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1. This will perform the same diagnostics as in step 3 Hold Steady Speed Hold a steady speed of 88km hr 55mph for five minutes During this time in addition to the diagnostics performed in step 4 the catalyst monitor diagnostics will be performed If the catalyst is marginal or the battery has been disconnected it may take 5 complete driving cycles to determine the state of the catalyst Decelerate This will perform the same diagnostics as in step 5 Again don t press the clutch or brakes or shift gears OBD II Page 24 3 7 2 Ford Motor Company Driving Cycle The following procedure is designed to execute and complete the OBD II monitors and to clear the Ford P1000 I M readiness code To complete a specific monitor for repair verification follow steps 1 through 4 and then continue with the step described by the appropriate monitor found under the OBD II Monitor Exercised column When the ambient air temperature is outside 4 4 to 37 8 C 40 to 100 F or the altitude is above 2438 meters 8000 feet the EVAP monitor will not run If the P1000 code must be cleared in these conditions the PCM must detect them once twice on some applications before the EVAP monitor can be bypassed and the P1000 cleared The EVAP bypassing procedure is described in the following drive cycle The OBD II Drive Cycle will be performed using a scan tool Drive Cycle Recommendations Most OBD II monitors will complete more readily2. P N 300ms 200 400 400 400 400 250 packet response 1 Wait for 300ms with K line high 2 send a byte 33 hex at 5 baud 200ms per bit startbit 200ms low databit0O 1 400ms high databit2 3 400ms low databit4 5 400ms high databit6 7 400ms low stopbit pause 250ms high 4 init serial connection to 10400 baud 8N1 1 0Volt O0 12Volt least significant bit first 5 send package cl 33 fl 81 66 33 dest fl our tester id 81 start comms 6 wait for response 83 f1 01 cl e9 8f ae 01 physical address cl response ok 7f fail e9 kb1 8f kb2 3 5 OBD II CONNECTORS he OBD I port s physical connector is called the Data Link Connector DLC It is a 16 pin plug that s usually located under the dashboard near the steering wheel The standard specifies that the connector must be within three feet of the driver The connector is located near the hood release in a difficult to photograph position This is shown is figure 3 4 One of the pins on the OBD II connector is power from the car s battery which means that OBD II readers do not need batteries or an external power source Another view to the connector itself is shown in figure 3 5 Figure 3 4 Example of the DLC location OBD II Page 19 Note When searching for your DLC remember that a three foot sphere around the driver is pretty large and the port may actually be on the passenger s side You can be fairly certain it will be hard to see and o
3. Driving Cycle A complete driving cycle should perform diagnostics on all systems A complete driving cycle can be done in less than fifteen minutes To perform an OBD II Driving cycle does the following Cold Start In order to be classified as a cold start the engine coolant temperature must be below 50 C 122 F and within 6 C 11 F of the ambient air temperature at startup Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run Idle The engine must be run for two and a half minutes with the air conditioner on and rear defroster on The more electrical load you can apply the better This will test the O2 heater Passive Air Purge No Flow Misfire and if closed loop is achieved Fuel Trim Accelerate Turn off the air conditioner and all the other loads and apply half throttle until 88km hr SSmph is reached During this time the Misfire Fuel Trim and Purge Flow diagnostics will be performed Hold Steady Speed Hold a steady speed of 88km hr 55mph for 3 minutes During this time the O2 response air Intrusive EGR Purge Misfire and Fuel Trim diagnostics will be performed Decelerate Let off the accelerator pedal Do not shift touch the brake or clutch It is important to let the vehicle coast along gradually slowing down to 32km hr 20 mph During this time the EGR Purge and Fuel Trim diagnostics will be performed Accelerate Accelerate at 3 4 throttle until 88 96 km hr 55 60mph
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5. RAY 30pF 10 gt 12V_PIN16 K LINE_PIN x 30 pF 10 Rd 124 GRD_PINS jt D R2 Figure 5 1 Project Schematic OBD II Page 32 5 1 2 Software Implementing the OBD2 controller firmware will be using high level programming language Embedded C Connecting and Testing Implementing a GUI based software on pc with C net to connect with the ODB 2 card by serial interface The ODB 2 standard used e ISO 9141 2 This protocol has a data rate of 10 4 k baud and is similar to RS 232 ISO 9141 2 is primarily used in Chrysler European and Asian vehicles pin 7 K line pin 15 L line optional UART signaling though not RS 232 voltage levels K line idles high High voltage is Vpat Message length is restricted to 11 bytes including CRC OBD II Page 33 OBD II REFERENCES 6 Published PDFs J On Board Diagnostic Hand Held Scan Tool Technology Arvon L Mitcham Lead Project Engineer On Board Diagnostics Certification and Compliance Division Office of Transportation and Air Quality U S Environmental Protection Agency October 2000 JE On Board Diagnostic Mitsubishi Motors Co orpration sE Evaluation of the impact of OBD systems and assessment of options for Euro 5 OBD Final Report Dimitrios Tsinoglou Zissis Samaras LABORATORY OF APPLIED THERMODYNAMICS MECHANICAL ENGINEERING DEPARTMENT ARISTOTLE UNIVERSITY T
6. a specific level of emission performance In addition the computer software coding and the OBD connection hardware were not standardized Recognizing the limitations of their OBD I systems the California Air Resources Board CARB developed a new set of OBD standards A standardized 16 pin Data Link Connector DLC with specific pins assigned to specific functions standardized electronic protocols standardized Diagnostic Trouble Codes DTCs and standardized terminology were outlined In the USA the federal government also decided to act in regard to standardizing OBD The EPA and CARB adopted a number of OBD standards established by the Society of Automotive Engineers SAE This new set of federal standards was labeled OBD II As a result of the federal Clean Air Act Amendments of 1990 in the USA these newer more advanced OBD II systems were built into all vehicles manufactured in the United States since 1 January 1996 In the USA 1996 model year and newer vehicles up to 14 000 pounds are typically equipped with OBD II systems All 1997 and newer diesel fueled passenger cars and trucks are also required to meet the OBD requirements In Canada OBD II became a regulated standard for Light Duty Vehicles LDVs for 1998 model year and newer vehicles We can summarize the evolution phase of the OBD systems even much longer before their appearance in the following table Year Event ALDL ALCL General Motors implements an interna
7. are enjoying the advantages of a fast amp reliable hardware An example for the above is provided in figure 3 6 a for the former and figure 3 7 b for the latter The components and systems monitored by the OBD II system can be divided into two general types lt Major monitors It consists of the misfire catalyst oxygen sensor exhaust gas recirculation EGR secondary air evaporative leak check and fuel systems These monitors are required to detect malfunctions and illuminate the MIL generally before emissions exceed 1 5 times the applicable Federal Test Procedure FTP standards The FTP is a special laboratory test that is required to be conducted by auto manufactures to show their vehicles comply with emission regulations before they are allowed for sale in California The test simulates city driving after the vehicle has been parked overnight The majority of OBD II monitors e g all the individual sensors valves solenoids etc fall under the comprehensive components category This category consists of input or output components that can cause an emission increase or are used to monitor any other monitored components systems e g the major monitors A general look for these sensor and components is provided in the next page figure 3 7 For example if the catalyst monitor is designed to run only when the vehicle is within a certain vehicle speed range the vehicle speed sensor needs to be monitored If it wasn t mon
8. board scan tool or F1 Header Byte 3 The third byte is the source This is the originating device of the data Sending data to the ECU 10 is usually done from the off board scan tool F1 Again this is flipped around when receiving data from the bus The only real difference between those headers and the one used for the ISO14230 KWP2000 is the first header byte Instead of the first byte being a priority the first byte is in the format 1 1 LLLLLL where the L s is a 6 bit number representing the length of the data packet being sent The vehicle responds with the same format only bit 6 is a zero in the format 1O LL LLLL CRC Check Byte The CRC check byte is computed through a formula provided by SAE so that the PCM can verify data integrity There are a lot of cables out there that will automatically calculate and add or strip off the CRC from the data communication 3 4 4 OBD II Message Initialization Supports ISO 9141 2 ISO 14230 2 K line transfer mode Fastinit AAAA 300ms 25ms 25ms packet response 1 Wait for 300ms with K line high 2 Pull K line low for 25 1 ms 3 Let K line rise high and wait 25ms OBD II Page 18 4 init serial connection to 10400 baud 8N1 1 0Volt O 12Volt least significant bit first 5 send package 6 wait for response 83 f1 01 cl e9 8f ae 01 physical address cl response ok 7f fail e9 kb1 8f kb2 Slowinit S 2 3 6 7 _ 0 1 4 5
9. competitive products we have a look to that in Section 4 Section 5 overviews our proposed project and the suggested circuitry Eventually we list the references used to implement this document in Section 6 OBD II Page 8 INYO DI OCO WO 2 2 1 WHAT IS OBD o Diagnostic system is a self diagnostic and reporting capability OBD systems give the vehicle owner or a repair technician access to state of health information for various vehicle sub systems The amount of diagnostic information available via OBD has varied widely since the introduction in the early 1980s of on board vehicle computers which made OBD possible Early instances of OBD would simply illuminate a Malfunction Indicator Light MIL if a problem were detected however it would not provide any information as to the nature of the problem Modern OBD implementations use a standardized fast digital communications port to provide real time data in addition to a standardized series of Diagnostic Trouble Codes DTCs which allow one to rapidly identify and remedy malfunctions within the vehicle 2 2 WHY IS THERE A NEED FOR OBD A higher the level of mobile emissions go as a higher need for reducing these emissions Thus the United States Environmental Protection Agency EPA has been charged with reducing mobile emissions from cars and trucks and given the power to require manufacturers to build cars which meet increasingly stiff emissions standards The manufacture
10. over a bus The CAN bus may be used in vehicles to connect engine control unit and transmission or on a different bus to connect the door locks climate control seat control etc Today the CAN bus is also used as a field bus in general automation environments this is especially because of the cheap prices of some CAN Controllers and processors The CAN standard is newly emerging It will be required on all new vehicles by 2008 and it will help various computer systems within your car to communicate For example your GPS system could talk to your OBD system or your DVD player OBD II Page 14 3 3 OBD II MODES OF OPERATION here are nine modes of operation described in the OBD II standard SAE J1979 They are Mode 1 This mode contains a large number of well defined data items Examples are vehicle speed RPM Fuel system status O2 Sensor voltages temperatures timing etc Mode 2 This mode retrieves Freeze frame data This data is a subset of the items in mode 1 but was stored at some point in the past when a trouble code was set Mode 3 This mode retrieves powertrain trouble codes also known as P codes Mode 4 This mode clears trouble codes It also clears all other stored diagnostic data such as freeze frames and on board test results Mode 5 This mode retrieves the results of Oxygen sensor tests for some vehicles Mode 6 This mode is used by some vehicles to report non continuously monitored test results Mode 7 T
11. CAIRO UNIVERSITY FACULTY OF ENGINEERING COMPUTER ENGINEERING DEPT 4 Year Product Development Automotive On Board Diagnostics OBD II G21_OBD H_PD01_v1_0 Prepared By Group No 12 Sec B N Amr Medhat Ahmed 3 6 Heba Khaled Abd Al Azeem 4 20 Mahmoud Ahmed Genedy 3 22 Mahmoud Ahmed Yassin 3 23 6 Mona Sayed Salem 4 12 Nesma Ahmed Mostafa 4 19 Shady Ismail Ahmed 2 16 Shaima Adel Mahmoud 2 17 Monitor Eng Aly El gamal Supervisor Dr Ra afat El Fouly TABLE OF CONTENTS Table of Contents 3 Index of Tables 5 Index of Figures 5 Glossary of Acronyms 6 1 Preface 8 1 1 Purpose 8 1 2 Scope 8 1 3 Approach 8 2 Introduction 9 2 1 What is OBD 9 2 2 Why is there a need for OBD 9 2 3 Historical Overview of ODB 9 3 OBD II Technical Overview 13 3 1 OBD II Basic Features 13 3 2 OBD II Diagnostic Trouble Codes 13 3 3 OBD II Modes of Operation 15 3 4 OBD II Standards and Protocols 15 3 4 1 All Standards 15 3 4 1 1 SAE Standards 15 3 4 1 2 ISO Standards 16 3 4 2 Common Protocols 16 3 4 3 OBD II Message Frame 17 3 4 4 OBD II Message Initialization 18 3 5 OBD II Connectors 19 3 6 OBD II Hardware and Implementation 20 3 7 OBD II Test Examples 24 3 7 1 GM Driving Cycle 24 3 7 2 Ford Motors Company Driving Cycle 25 4 OBD II Market and Future 28 4 1 OBD II Market 28 4 1 1 Suggested Market Surve 28 4 1 2 OBD II Product Samples i
12. HESSALONIKI On Board Diagnostics II OBDII and Light Duty Vehicle Emission Related Inspection and Maintenance I M Programs D Cope Enterprises April 2004 URLs a http www autoshop101 com forms h46 pdf ES http www fordscorpio co uk obdindetail htm ps http www vericomcomputers com OBDII htm Es http www epa gov otaq regs im obd r00017 pdf ES http www obdii com http www epa state il us air vim faq obdlong html ak http www thinkythings org obdii ES http www 4x4wire com toyota 4Runner tech BR 3 ps http en wikipedia org wiki On_Board_Diagnostics 4 http en wikipedia org wiki OBD II_PIDs http www obd2crazy com techstd html A http www nology com pdfandzipfiles obdiicodes pdf OBD II Page 34
13. I section in the service manual Depending on the year and the vehicle a car with the OBD 1 5 system may have either the older OBD I connector or the newer OBD II connector but they are electrically identical to each other For example the 94 95 Corvettes have one post cat oxygen sensor although they have two catalytic converters and have a subset of the OBD II codes implemented The pinout for the ALDL connection on these cars is as follows 1986 1987 1994 OBD II Page 11 92345678 910111213141516 For ALDL connections pin 9 is the data stream pins 4 and 5 are ground and pin 16 is battery voltage Additional vehicle specific diagnostic and control circuits are available on this connector For instance on the Corvette there are interfaces for the Class 2 serial data stream from the PCM the CCM diagnostic terminal the radio data stream the airbag system the selective ride control system the low tire pressure warning system and the passive keyless entry system An OBD1 5 has also been used on Mitsubishi cars of 95 97 vintage Motivated by a desire for a state wide emissions testing program the CARB issues the OBD II specification and mandates that it 1994 be adopted for all cars sold in California starting in model year 1996 The DTCs and connector suggested by the SAE are incorporated into this specification OBD II OBD II is an improvement over OBD I in both cap
14. LDL connector An upgraded version of the ALDL protocol appears which communicates at 8192 baud with half duplex UART signaling OBD I CARB requires that all new vehicles sold in California starting in manufacturer s year 1988 have some basic OBD capability The requirements they specify are generally referred to as the OBD I standard though this name is not applied until the introduction of OBD II The data link connector and its position are not standardized nor is the data protocol The regulatory intent of OBD I was to encourage automobiles manufacturers to design reliable emission control systems that remain effective for the vehicle s useful life The hope was that by forcing annual emissions testing for California and denying registration to vehicles that did not pass drivers would tend to purchase vehicles that would more reliably pass the test Along these lines OBD I was largely unsuccessful the means of reporting emissions specific diagnostic information was not standardized Technical difficulties with obtaining standardized and reliable emissions information from all vehicles led to an inability to effectively implement the annual testing program OBD 1 5 4 OBD 1 5 is a slang term referring to a partial implementation of OBD II which GM used on some vehicles in 1994 and 1995 GM did not use the term OBD 1 5 in the documentation for these vehicles they simply have an OBD and an OBD I
15. ability and standardization The OBD II standard specifies the type of diagnostic connector and its pinout the electrical signaling protocols available and the messaging format It also provides a candidate list of vehicle parameters to monitor along with how to encode the data for each Finally the OBD II standard provides an extensible list of DTCs As a result of this standardization a single device can query the on board computer s in any vehicle This simplification of reporting diagnostic data led the feasibility of the comprehensive emissions testing program envisioned by the CARB The European Union makes EOBD a variant of OBD II 2001 mandatory for all petrol vehicles sold in the European Union starting in model year 2001 Table 1 1 OBD Timeline 1996 OBD II Page 12 OBD II TECHNICAL OVERVIEW 3 3 1 OBD II BASIC FEATURES hen a problem that could cause a substantial increase in air emissions is detected the OBD II system turns on a dashboard warning light the Malfunction Indicator Light MIL to alert the driver of the need to have the vehicle checked by a repair technician A repair technician can then ascertain the status of various vehicle systems by connecting a scan tool to the standardized connector the Diagnostic or Data Link Connector In general three pieces of information can be downloaded from a vehicle s OBD II system with a scan tool Whether the emission
16. cle information including VIN if your vehicle is able to provide that Rescans Data Easy to use with one plug in Highly reliable and accurate Easy to read crystal clear backlit LCD display OBD II Page 28 Stand alone unit with no need for an additional laptop computer to operate Performs continuous DTC scan Safely communicates with the on board computer Protocols This reader works on the following protocols SAE J1850 PWM SAE J1850 VPW ISO 9141 2 e ISO 14230 4 KWP 2000 ISO 15765 4 SAE J2480 Controller Area Network CAN Price 89 0 4 1 2 3 Product 3 The CJ4 ProPack OBD CAN Scantool amp Oscilloscope w Enhanced Applications Overview The Injectronic CJ4 OBD II Scan Tool and Labscope are designed to help technicians and motorists fix vehicles faster supporting three important approaches of automotive diagnostics The scan tool feature allows to communicate with the Electronic Control Unit ECU of the vehicles to retrieve Diagnostic Trouble Codes and live data from parameters like temperature RPMs etc and status of sensors and actuators The kind of information retrieved is what the ECU of the vehicle sees For example it can say that a temperature sensor is low or high but it won t tell you if the cause is a wire connector an ECU or the sensor itself That s why a labscope is needed because it helps to pinpoint the failure as it sees
17. eISO9141 2 eJ1850 VPW J1850 PWM Output Protocol Bluetooth or RS232 Indicat or LEDs Power OBD Tx Rx RS232 Tx Rx Operation Voltage 12V internal protection from short circuits overvoltages Dimensions 6 7 x 1 7 170 mm x 43 mm Price 190 0 4 1 2 2 Product 2 OBD 2 Auto Scanner Tool OBD2 OBD II II CAN Code Reader UPDATABLE VIA THE INTERNET Overview This auto scanner OBD II car reader easily connects to the diagnostic socket and will quickly find your trouble issues by reading the specific diagnostic trouble codes DTC and shows their description as well Moreover this tool is able to display live data from your car s computer such as current RPM engine coolant temperature vehicle speed oxygen sensor data and much more Newly launched model with wider vehicle coverage as it supports the CAN Protocol Features e Works with 1996 and newer cars amp trucks that are OBD II compliant including the VPW PWM ISO KWP 2000 and CAN protocols Reads and clears generic and manufacturer specific Diagnostic Trouble Codes DTC Updatable via the Internet using RS 232 serial port Turns off check engine light Trouble codes and code meanings display on the LCD display No code book is needed lt Displays live data Supports multiple trouble code requests generic codes pending codes and manufacturer s specific codes Reads Freeze Frame Data Tests I M Reading Status Reads vehi
18. encing For example the DTC P0302 means cylinder 2 misfire detected If the condition that caused the DTC persists OBD II Page 20 the car s computer will turn on the malfunction indicator light DTCs are fully explained in subsection 3 2 Real time data is the raw sensor data reported to the OBD computer This data can be helpful for troubleshooting problems and monitoring engine performance Freeze frame data is a snapshot of the real time sensor feeds at the time of a DTC condition An auto mechanic can use this data to figure out what was going on at the time your car s check engine light went on OBD II hardware breaks down into two categories stand alone devices that are intended exclusively for diagnostics and signal conversion tools that provide a physical connection but require software on a computer or PDA to display the data Obviously the conversion tools will be slightly cheaper because they are only interfacing to the vehicle and have no processor or memory They re also more flexible because the software can be replaced or modified In the stand alone devices the PDA or the computer can be replaced by a microcontroller or a FPGA Thus you develop the code to work under a specific protocol or protocols then you burn your code to the programmable device and connect it to the car In that case we can gain the advantages of a flexible system as the software of the FPGA or the microcontroller is easy to update while we
19. es gt When something goes wrong with my car or truck I o Take it to a trusted mechanic o Already know how to most repairs so dive right and fix it o Research how to fix it online or by asking friends then decide if I should do it myself or take it to a shop o Swear a few times and keep driving Results about 40 would take it to a mechanic 10 know how to repair it 30 would research and 20 would keep on driving 4 1 2 OBD II Product Samples in the Market 4 1 2 1 Product 1 The ElmScan 5 Wireless Bluetooth enabled OBD2 Scan Tool Kit Features The package includes everything you need including the USB to Bluetooth adapter for your laptop or PC and the OBD scan tool kit with the cable to the OBD port on your car The Bluetooth module included with this top rated OBD scan tool is a Class 1 device capable of line of sight communication at distances of up to 100 meters 300 ft and the signal strength is sufficient to enable close range communication through walls and other obstacles The ElmScan 5 Wireless OBD II Scan Tool is modular and comes with a six foot OBD II cable which allows the device to be placed on the dashboard or the roof of the vehicle for best reception When used in environments with an extremely high level of electromagnetic noise the Bluetooth module can be unplugged and replaced with a serial cable OBD II Page 27 OBD I Protocols e1SO15765 4 CAN eISO14230 4 KWP2000
20. his mode reports the results of continuously monitored test results It uses the same format as trouble codes but the information is available after a single driving cycle Mode 8 This mode was intended to request control of on board devices Very little has been generically defined Mode 9 This mode reports information such as the vehicle s VIN number and calibration constants Note that modes 1 and 2 are basically identical except that Mode 1 provides current information whereas Mode 2 provides a snapshot of the same data taken at the point when the last diagnostic trouble code was set The exceptions are PID 01 which is only available in Mode 1 and PID 02 which is only available in Mode 2 If Mode 2 PID 02 returns zero then there is no snapshot and all other Mode 2 data is meaningless 3 4 OBD II STANDARDS AND PROTOCOLS 3 4 1 All Standards 3 4 1 1 SAE Standards J1962 Defines the physical connector used for the OBD II interface J1850 Defines a serial data protocol There are 2 variants 10 4 Kbit s single wire VPW and 41 6 Kbit s 2 wire PWM Mainly used by US manufacturers also known as PCI Chrysler 10 4K Class 2 GM 10 4K and SCP Ford 41 6K se J1978 Defines minimal operating standards for OBD II scan tools J1979 Defines standards for diagnostic test modes J2012 Defines standards trouble codes and definitions gt PS SG OBD II Page 15 e J2178 1 Define
21. itored the vehicle speed sensor OBD II Page 21 could malfunction the catalyst monitor would never run and the system would never know if the catalyst was still working properly or not lt Comprehensive components also include any component that when malfunctioning can cause an emission increase during any reasonable driving condition whether it be idle cold start acceleration cruising or any other condition So even though a malfunctioning component may not seem to cause an emission increase during some conditions it probably does under other driving conditions For all comprehensive components the MIL is required to illuminate when any individual component is out of specification or fails to work when commanded Generally the OBD II system is required to illuminate the MIL after the same fault has been found in two different driving cycles which helps to ovoid MIL illumination for random faults or abnormal conditions The MIL is only allowed to extinguish when the same fault has not been detected on three successive driving cycles Diagnostic Trouble Codes DTCs remain stored for around 40 driving cycles to make sure that information is still available to repair technicians even after the MIL is extinguished GAN DNA a b Figure 3 6 OBD II Hardware Examples a stand alone device b converter card to be connected to a computer or a PDA for diagnosis OBD II Page 22 uwa JJOSN3S IN GEN OSE
22. l 64 Km h 40 MPH no brakes Repeat this 3 times Allows learning for the misfire monitor Readiness Check 12 Access the ON Board System Readiness OBD II monitor status function on the scan tool Determine whether all non continuous monitors have completed If not go to step 13 Determines if any monitor has not completed Pending Code Check and Evap Monitor Bypass Check 13 With the scan tool check for pending codes Conduct normal repair procedures fol any pending code concern Otherwise rerun any incomplete monitor Note if the EVAP monitor is not complete AND IAT was out of the 4 4 to 37 8 C 40 to 100 F temperature range in step 4 or the altitude is over 2438 m 8000 ft the Evap bypass procedure must be followed Proceed to step 14 Determines if a pending code is preventing the clearing of P1000 Evap Monitor Bypass 14 Park vehicle for a minimum of 8 hours Repeat steps 2 through 12 DO NOT REPEAT STEP 1 Allow the bypass counter to increment td two OBD II Page 26 OBD II MARKET AND FUTURE 4 4 1 OBD II MARKET 4 1 1 Suggested Market Survey Here we try to suggest a market survey to measure the OBD II market potentials through answering some questions gt Do you own a 1996 car or light truck YesO NoO Results 80 Yes gt Have you had the Check Engine light on in your vehicle YesO NoO Results 57 out of the 80 answered Y
23. l standard for its OBD called the Assembly Line Communications Link ALCL later renamed the Assembly Line Diagnostics Link ALDL The initial ALCL protocol communicates at 160 baud with Pulse width modulation PWM signaling and monitors very few vehicle systems This system was only vaguely standardized and suffered from the fact that specifications for the communications link varied from 1982 one model to the next l l l ALDL was largely used by manufacturers for diagnostics at their dealerships and official maintenance facilities There were at least three different connectors used with ALDL General Motors implemented both a 5 pin connector and a 12 pin connector with the 12 pin connector being used in the vast majority of GM cars while Lotus implemented a 10 pin connector The pins are given letter designations in the following layouts as seen from the front of the vehicle connector e 12 pin ALDL connector pinout OBD II Page 10 FEDCBA GHJKLM e 10 pin ALDL connector pinout ABCDE KJHGF e 5 pin ALDL connector pinout ABCDE Unfortunately the definition of which signals were present on each pin varied between vehicle models There were generally only three pins used for basic ALDL ground battery voltage and a single line for data although other pins were often used for additional vehicle specific diagnostic information and control interfaces No battery voltage is present in the 12 pin A
24. mputer using the scan tool There are now over 400 possible trouble OBD II Page 13 codes that can be stored in the OBD II system Other manufacturer specific codes may also set by the OBD II system A standard set of DTCs is available on all vehicles but each manufacturer includes hundreds of proprietary codes that help pinpoint malfunctions on a specific vehicle Real time data sent through the OBD port includes vehicle speed RPMs air temperature and the readings of various sensors Now this introduces us to a new term Parameter IDs PIDs that are codes used to requests data from a vehicle used as a diagnostic tool Typically a car mechanic will use PIDs with a scan tool connected to the vehicle s OBD II connector The Event Flow as e The mechanic enters the PID e The scan tool sends to the vehicle s CAN bus e A device on the bus recognizes the PID as one it is responsible for and reports the value for that PID to the CAN Bus e The scan tool reads the response and shows it to the mechanic An example of a PID amp how to translate it is shown in figure 3 1 Example P0500 Vehicle Speed Sensor Malfunction Serial numbering System or Component O or 2 SAE ISO Standard code 1 or 3 Manufacturer specific Power train SAE classification Body Chassis Network Figure 3 1 PID example Note Controller Area Network CAN is a communication system whereby multiple nodes connect to and communicate
25. n the Market 28 4 1 2 1 Product 1 27 4 1 2 2 Product 2 28 4 1 2 3 Product 3 29 4 1 2 4 Product 4 30 4 2 OBD II Future 31 5 OBD II Proposed Project 32 5 1 Project Objective 32 OBD II Page 3 5 1 1 Hardware 5 1 2 Software 32 5 1 1 1 OBD II Interface Card PCB 32 5 1 1 2 OBD II Cable 32 5 1 1 3 Schematic 32 33 34 6 References OBD II Page 4 INDEN OF TABLES Table 1 1 OBD Timeline 10 Table 3 1 Common used protocols 17 Table 3 2 Header Byte 1 Bits 3 0 Function 18 INDEX OF FIGURES Figure 3 1 PID Example 14 Figure 3 2 OBD II Message Frame Organization 17 Figure 3 3 Header Byte 1 Structure 17 Figure 3 4 Example of the DLC location 19 Figure 3 5 OBD II DLC 20 Figure 3 6 OBD Hardware Examples 22 Figure 3 7 Engine Installed Sensors 23 Figure 5 1 Project Schematic 32 OBD II Page 5 GLOSSARY OF ACRONYMS In the order of their appearance in the document Notation Abbreviation OBD On Board Diagnostics ECU Engine Control Unit MIL Malfunction Indicator Light DTC Diagnostics Trouble Codes EPA Environmental Protection Agency CARB California Air Resources Board DLC Data Link Connector SAE Society of Automotive Engineers LDV Light Duty Vehicles ALDL Assembly Line Diagnostics Link ALCL Assembly Line Communications Link PWM Pulse Width Modulation UART Universal Asynchronous Receiver Transmitter CCM Continuous Current M
26. ode PCM Pulse Code Modulation E OBD European OBD OBD II EGR Exhaust Gas Recirculation RPM Revolutions per Minute PID Parameter ID CAN Controller Area Network ISO International Standardization Organization VPW Variable Pulse Width CRC Cyclic Redundancy Check FPGA Field Programmable Gate Array FTP Federal Test Procedure OBD II Page 7 PREFACE 1 1 1 PURPOSE This document will try to cover the following issues gt OBD its importance versions and standards gt How to Implement an OBD gt OBD in the market gt Future of OBD 1 2 SCOPE this document we hope to provide an insight into the OBD We want to get more familiar with car embedded systems that have been widely used since 1996 OBD along with FCU s become the brain and the immunity system of any new vehicle We provide here details on the versions of OBD since it was introduced to the car industry Also we will have a look on the standards used in the market An important question will arise it s how to implement an OBD this is provided along with a simple market analysis study and the future waiting for OBD 1 3 APPROACH his Document starts by providing by introducing the term of OBD to the reader what it should mean to him in his life its need amp its history in Section 2 In Section 3 we provide the reader with what he needs to get involved in the OBD industry and communication In our concern with the market potentials and the
27. r reach though Pin 2 J1850 Bus Pin 4 Chassis Ground Pin 5 Signal Ground Pin 6 CAN High J 2284 Pin 7 ISO 9141 2 K Line Pin 10 J1850 Bus Pin 14 CAN Low J 2284 Pin 15 ISO 9141 2 L Line Pin 16 Battery Power Figure 3 5 OBD I DLC Now concerning the protocols used to implement OBD II in various vehicles as mentioned in the subsection 3 4 2 the connector meets each protocol specification as follow lt J1850 VPW The connector should have metallic contacts in pins 2 4 5 and 16 but not 10 4 ISO 9141 2 The connector should have metallic contacts in pins 4 5 7 15 and 16 J1850 PWM The connector should have metallic contacts in pins 2 4 5 10 and 16 While there are three OBD II electrical connection protocols the command set is fixed according to the SAE J1979 standard Note If your vehicle has this style connector but doesn t have these pins populated you probably have a pre OBD II vehicle To add some confusion even having the connector with the contacts shown above is not a guarantee of OBD II compliance This style connector has been seen on some pre 1996 vehicles which were not OBD II compliant 3 6 OBD II HARDWARE AND IMPLEMENTATION he OBD II port allows your car to report three kinds of information Diagnostic Trouble Codes real time data and freeze frame data DTCs are simply error codes that can be looked up to determine what problem the car is experi
28. rs must further maintain the emission standards of the cars for the useful life of the vehicle So here comes the need for OBD to provide a universal inspection and diagnosis method to be sure the car is performing to the required standards Also the nice thing about OBD II specifically is that it provides a way to monitor the vehicle health in real time The data provided by OBD II can often pinpoint the specific component that has malfunctioned saving substantial time and cost compared to guess and replace repairs Scanning OBD II signals can also provide valuable information on the condition of a used car purchase Note Two factors will show if your vehicle is definitely OBD II equipped 1 There will be an OBD II connector as shown below and 2 There will be a note on a sticker or nameplate under the hood OBD II compliant 2 3 HISTORICAL OVERVIEW OF OBD he first widespread use of OBD to monitor emissions control components and parameters was in California in the 1990s In California On Board Diagnostics I OBD I was California s first set of OBD regulations that required manufacturers to install OBD systems that monitored some of the emission control components on vehicles Although OBD II Page 9 OBD I systems were required on all 1991 and newer vehicles sold in California these OBD I systems were not particularly effective because they only monitored a few emission related components and they were not calibrated to
29. s MODE 6 information OBD II connector locator help Protocols supported CAN J1850 ISO9141 KWP 2000 ISO 14230 4 SCI and CCD Price 799 2e kS x kS 2e 2e kS 2e kS NA 4 2e kS 2e kS S 2e kS x kS 2e kS 2e kS x kS x kS 4 1 2 4 Product 4 ElmScan 5 serial Features ElmScan 5 is the most widely used PC based product from ScanTool net Based on the ELM327 IC the ElmScan5 supports all OBD II protocols and is compatible with a number of software applications including open source software Block Diagram illustrating how the scan tool ElmScan connects between the vehicle amp the host Computer computer vere BD cable Saf tol ceil Cable aac OBD II Page 30 Processor ELM327 OBD II Protocols e 1SO15765 4 CAN e ISO14230 4 KWP2000 e ISO9141 2 e J1850 VPW e J1850 PWM Output Protocol RS232 Baud Rate 9600 or 38400 Indicat or LEDs Power OBD Tx Rx RS232 Tx Rx Operation Voltage 12V internal protection from short circuits overvoltages Dimensions 3 75 x 1 7 95 mm x 43 mm Price 125 0 4 2 OBD II FUTURE he OBD II federal OBD uses the same basic technical standards as California OBD II debate comes to a close speculation is already mounting about an OBD III concept in California OBD II is being discussed as a program to minimize the delay between the detection of an emissions malfunc
30. s Malfunction Indicator Light MIL commanded on or off lt Which if any manufacturer fault codes or Diagnostic Trouble Codes are stored i e have been activated e The status of the Readiness Monitors The current OBD II systems monitor the status of up to 11 emission control related subsystems by performing either continuous or periodic functional tests of specific components and vehicle conditions The three categories monitored on a continuous basis are misfire fuel trim and comprehensive components The remaining eight subsystems are only monitored after a certain set of conditions have been met or periodically The algorithms for running these eight periodic monitors are unique to each manufacturer and involve such things as ambient temperature as well as driving conditions Most vehicles will have at least five of the eight monitors amp the final three systems are not necessarily applicable to all vehicles e Catalyst e Evaporative system or leak check e Oxygen sensor e Heated oxygen sensor e Exhaust Gas Recirculation EGR system e Air conditioning e Secondary air e Heated catalyst 3 2 OBD II DIAGNOSTIC TROUBLE CODES hen the OBD II computer detects a problem it sets and stores a Diagnostic Trouble Code or Fault Code When a car is taken in for diagnosis or for an annual emissions inspection the repair technician retrieves any set Diagnostic Trouble Codes or fault codes from a vehicle s co
31. s standards for network message header formats and physical address assignments se J2178 2 Gives data parameter definitions se J2178 3 Defines standards for network message frame IDs for single byte headers e J2178 4 Defines standards for network messages with three byte headers J2284 3 Defines 500K CAN Physical and Data Link Layer 3 4 1 2 ISO Standards 7 ISO 9141 Road vehicles Diagnostic systems International Organization for Standardization 1989 o Part 1 Requirements for interchange of digital information o Part 2 CARB requirements for interchange of digital information o Part 3 Verification of the communication between vehicle and OBD II scan tool ISO 11898 Road vehicles Controller area network CAN International Organization for Standardization 2003 o Part 1 Data link layer and physical signaling o Part 2 High speed medium access unit o Part 3 Low speed fault tolerant medium dependent interface o Part 4 Time triggered communication ISO 14230 Road vehicles Diagnostic systems Keyword Protocol 2000 International Organization for Standardization 1999 o Part 1 Physical layer o Part 2 Data link layer o Part 3 Application layer o Part 4 Requirements for emission related systems ISO 15765 Road vehicles Diagnostics on CAN International Organization for Standardization 2004 o Part 1 General information o Part 2 Network layer
32. services o Part 3 Implementation of unified diagnostic services UDS on CAN o Part 4 Requirements for emissions related systems 3 4 2 Common Protocols Within the OBD II standard there are several protocols for transferring data from the car to a diagnostic device As a rule of thumb GM cars and light trucks use SAE J1850 VPW Chrysler products and all European and most Asian imports use ISO 9141 circuitry Fords use SAE J1850 PWM communication patterns OBD II Page 16 There are some variations among captive imports such as the Cadillac Catera a German Opel derivative which uses the European ISO 9141 protocol The most common are Name Speed Used by ISO 9141 10 Kbits sec most Asian and European manufacturers SAE J1850 PWM 100 Kbits sec Ford Mazda SAE J1850 VPW 100 Kbits sec primarily GM CAN varies by application newer vehicles Table 3 1 Commonly Used Protocols Note When shopping for an OBD tool one need to make sure it supports the protocol his vehicle uses but after that he probably don t need to worry about the protocol 3 4 3 OBD II Message Frame The OBD message frame consists of 3 parts the header data and CRC The general format for the message is as follows Header 1 Header 2 Header 3 Data 1 Data 2 Data 3 Data 4 Data 5 Data 6 Data 7 CRC Figure 3 2 OBD Message Frame Organization The typical message must have all three header bytes from 1 to 7 data b
33. the signals traveling in the electrical wiring of the car The CJ4 9240 Scan Tool uses a plug in module design to allow you to add enhanced data amp optional testing accessories as needed The CJ4 is the only automotive tool that really works on the main three steps of diagnostics within the vehicle SCANTOOL Communications with the ECU PCM of OBD II vehicles LABSCOPE View and capture signal waveforms present in the electrical wiring INTERFACE MODE The CJ4 enters a slave mode so a PC or PDA can take control of communications with the ECU of the vehicle USB or serial communications supported Features e Easy navigation only six keys Illuminated 128x128 pixels LCD display Powered by vehicle No batteries needed OBD II Page 29 2e Bilingual operation English and Spanish USB and serial communication ports Internet upgradable Accepts CJPort modules with Secure Data SD cards Screenshot capture for later view or PC download PC software to upload screenshots and view data in graph and numeric formats Acronyms database OBD II Functions Retrieve and clear trouble codes 4 Retrieve live data of OBD II 1996 2007 Global OBD II parameters PO P1 P2 P3 UO and U1 DTCs English and Metric units of measure Freeze Frame Data Monitor Status Readiness status Turns off Check engine lights Complete parameter names Vehicle ID Mode 9 Graph cursor It display
34. tion by the OBD II system and the actual repair of the vehicle This includes a reading of stored OBD II information from in use vehicles and the direction to owners of vehicles with fault codes to make immediate repairs In this concept faults are picked up by a monitoring technology and reported to a regulator and the vehicle owner is then directed to get further testing and possible repairs The debate over controlling vehicle emissions may soon move from what type of testing facilities and test methods are most effective to the complete on board cycle of fault detection notification and follow up testing and repair being discussed in the OBD III concept OBD II Page 31 OBD II PROPOSED PROJECT 5 5 1 PROJECT OBJECTIVE Designing an ODB 2 interface card powered by a microcontroller and interfaced with a laptop by a serial port 5 1 1 Hardware 5 1 1 1 OBD II Interface Card PCB This card is designed around an ATMEL 80C52 microcontroller The 8052 is an enhanced version of the original Intel 8051 that featured 256 bytes of internal RAM instead of 128 bytes 8 kB of ROM instead of 4 kB and a third 16 bit timer 5 1 1 2 OBD II Cable The adapter uses 9 pin D type female connector to link up to vehicle s OBD2 J1962 connector The pin out matches many of the commercially available cables 5 1 1 3 Schematic gt z wuwung AS BRR GRE S AAK cS sa ggBRgRGHSHESESSR RUPE RER
35. tor 6 Cruise at 72 to 104 Km h 45 to 65 MPH Executes the EVAP OBD II Page 25 for 10 minutes avoid sharp turns and hills Note to initiate the monitor TP MODE should PT EVAPDC must be gt 75 and FLI must be between 15 and 85 Monitor If IAT is withi 4 4 to 37 8 40 to 100 F 7 Drive in stop and go traffic conditions Include five different constant cruise speeds ranging from 40 to 72 Km h 25 to 45 MPH over a 10 minute period Executes the Catalyst Monitor SEC AIR CCM Engine 8 From a stop accelerate to 72 Km h 45 MPH at 1 2 to 3 4 throttle Repeat 3 times 9 Bring the vehicle to a stop Idle with transmission in drive neutral for M T for 2 minutes Executes the EGR Monitor Executes the ISC portion of the CCM CCM Trans 10 For M T accelerate from 0 to 80 Km h 0 to 50 MPH continue to step 11 For A T from a stop and in overdrive moderately accelerate to 80 Km h 50 MPH and cruise for at least 15 seconds Stop vehicle and repeat without overdrive to 64 Km h 40 MPH cruising for at least 30 seconds While at 64 Km h 40 MPH activate overdrive and accelerate to 80 Km h 50 MPH and cruise for at least 15 seconds Stop for at least 20 seconds and repeat step 10 five times Executes the transmission portion of the CCM Misfire amp Fuel Monitors 11 From a stop accelerate to 104 Km h 65 MPH Decelerate at closed throttle unti
36. using a steady foot driving style during cruise or acceleration modes Operating the throttle in a smooth fashion will minimize the time required for monitor completion Fuel tank level should be between 1 2 and 3 4 fill with 3 4 fill being the most desirable The Evaporative Monitor can only operate during the first 30 minutes of engine operation When executing the procedure for this monitor stay in part throttle mode and drive in a smooth fashion to minimize fuel slosh For best results follow each of the following steps as accurately as possible OBD II Monitor Drive Cycle Procedure Purpose of Exercised Drive Cycle Procedure Drive Cycle 1 Install scan tool Turn key on with the Bypasses engine soak Preparation engine off Cycle key off then on Select timer Resets OBD II appropriate Vehicle amp Engine qualifier Clear Monitor status all DTC s Perform a PCM Reset 2 Begin to monitor the following PIDs ECT EVAPDG FLI if available and TP MODE Start vehicle WITHOUT returning to Key Off 3 Idle vehicle for 15 seconds Drive at 64 Km h 40 MPH until ECT is at least 76 7 C 170 F Prep for Monitor 4 Is IAT within 4 4 to 37 8 C 40 to 100 F Engine warm up and Entry If Not complete the following steps but provide IAT input to thg note that step 14 will be required to PCM bypass the Evap monitor and clear the P1000 5 Cruise at 64 Km h 40 MPH for up to 4 Executes the HEGO minutes moni
37. ytes and the CRC The CRC is occasionally added and stripped by the cable depending on the hardware The CRC byte has a specific calculation the formula for which is provided a little later on this subsection For the VPW and PWM protocols the header is set up like this Header Byte 1 This byte is what is called priority and is usually a value of 6C hex or 68 hex The byte structure is a bit confusing so here is a breakdown of it Bit 7 Priority Bits 000 high 111 low Bit 6 Bit 5 Bit 4 Header Style 0 3 byte header GM 1 Unknown Bit 3 In Frame Response 0 Required Ford 1 Not Allowed GM Bit 2 Addressing Mode 1 Physical 0 Functional Bit 1 Message Type Bit 0 Figure 3 3 Header Byte 1 Structure OBD II Page 17 The following table breaks down the last 4 bits of the header byte 1 Addressing Bit3 Bit2 Bit1 Bit0 Functional 1 0 0 0 Function 1 0 0 1 Broadcast 1 0 1 0 Query 1 0 1 1 Read Physical 1 1 0 0 Node To Node 1 1 0 1 Reserved 1 1 1 0 Reserved 1 1 1 1 Reserved Table 3 2 Header Byte 1 Bits 3 0 Functions Header Byte 2 The second byte is something referred to as the target The target is the device on the bus that you wish to address A common device to address on the bus is 10 which is the ECU When you get a response back from the ECU the 10 will become the third byte in the header and the target will be the off
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