1、Copyright 1996 Society of Automotive Engineers, Inc.All rights reserved.J1979REV.SEP97E/E DIAGNOSTIC TEST MODESTABLE OF CONTENTS1. Scope . 32. References . 42.1 Applicable Publications 42.1.1 SAE Publications 42.1.2 ISO Publications. 42.1.3 California ARB Publications 42.1.4 Federal EPA Publications
2、. 4SAE J1979SAE J1979 Revised SEP97-2-3. Definitions .43.1 Absolute Throttle Position Sensor 43.2 Bank43.3 Base Fuel Schedule43.4 Calculated Load Value53.5 Continuous Monitoring53.6 Fuel Trim.54. Technical Requirements .54.1 Diagnostic Test Mode General Conditions .54.1.1 Multiple Responses to a Sin
3、gle Data Request .54.1.2 Response Time.54.1.3 Minimum Time Between Requests From Scan Tool.54.1.4 Data Not Available 54.1.5 Maximum Values 64.2 Diagnostic Message Format .64.2.1 Addressing Method.64.2.2 Maximum Message Length.64.2.3 Diagnostic Message Format .64.2.4 Header Bytes74.2.5 Data Bytes 74.
4、2.6 Non-Data Bytes Included in Diagnostic Messages With SAE J185074.2.7 Non-Data Bytes Included in Diagnostic Messages With ISO 9141-2 .74.2.8 Bit Position Convention.84.3 Allowance for Expansion and Enhanced Diagnostic Test Modes.84.4 Format of Data to be Displayed 85. Test Modes .95.1 Mode $01Requ
5、est Current Powertrain Diagnostic Data .95.1.1 Functional Description 95.1.2 Message Data Bytes.95.2 Mode $02Request Powertrain Freeze Frame Data.95.2.1 Functional Description 95.2.2 Message Data Bytes.105.3 PIDs for Modes $01 and $02105.4 Mode $03Request Emission-Related Powertrain Diagnostic Troub
6、le Codes .175.4.1 Functional Description 175.4.2 Message Data Bytes.185.4.3 Powertrain Diagnostic Trouble Code Example .195.5 Mode $04Clear/Reset Emission-Related Diagnostic Information .205.5.1 Functional Description 205.5.2 Message Data Bytes.205.6 Mode $05Request Oxygen Sensor Monitoring Test Res
7、ults 205.6.1 Functional Description 205.6.2 Message Data Bytes.215.7 Mode $06Request On-Board Monitoring Test Results245.7.1 Functional Description 245.7.2 Message Data Bytes.255.7.3 Message Example 285.8 Mode $07Request On-Board Monitoring Test Results305.8.1 Functional Description 305.8.2 Message
8、Data Bytes.305.9 Mode $08Request Control of On-Board System, Test, or Component.315.9.1 Functional Description 31SAE J1979 Revised SEP97-3-5.9.2 Message Data Bytes.315.9.3 Test ID and Data Byte Descriptions325.10 Mode $09Request Vehicle Information .325.10.1 Functional Description 325.10.2 Message D
9、ata Bytes.335.10.3 Vehicle Information Types and Data Byte Descriptions335.10.4 Message Example 356. Notes 366.1 Marginal Indicia.361. ScopeThis SAE Recommended Practice defines diagnostic test modes, and request and responsemessages, necessary to be supported by vehicle manufacturers and test tools
10、 to meet the requirements of theCalifornia OBD II and Federal OBD regulations, which pertain to vehicle emission-related data only. Thesemessages are intended to be used by any service tool capable of performing the mandated diagnostics.In addition, capabilities are defined that are intended to meet
11、 other Federal and State regulations pertaining torelated issues such as Inspection and Maintenance (I/M) and service information availability. This documentprovides the mechanism to satisfy requirements included in regulations, and not all capabilities included in thisdocument are required by regul
12、ations. This document also is not considered a final authority for interpretationof the regulations, so the reader should determine the applicability of the capabilities defined in this documentfor their specific need.Diagnostic Test Modes included in this document are:a. Mode $01Request Current Pow
13、ertrain Diagnostic DataAnalog inputs and outputsDigital inputs and outputsSystem status informationCalculated valuesb. Mode $02Request Powertrain Freeze Frame DataAnalog inputs and outputsDigital inputs and outputsSystem status informationCalculated valuesc. Mode $03Request Emission-Related Powertra
14、in Diagnostic Trouble Codesd. Mode $04Clear/Reset Emission-Related Diagnostic Informatione. Mode $05Request Oxygen Sensor Monitoring Test Resultsf. Mode $06Request On-Board Monitoring Test Results for Non-Continuously Monitored Systemsg. Mode $07Request On-Board Monitoring Test Results for Continuou
15、sly Monitored Systemsh. Mode $08Request Control of On-Board System, Test, or Componenti. Mode $09Request Vehicle lnformationFor each test mode, this specification includes:a. Functional descriptions of test modeb. Request and response message formatsFor some of the more complex test modes, an exampl
16、e of messages and an explanation of the interpretationof those messages is included.SAE J1979 Revised SEP97-4-2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein. Unless otherwise specified, the latest issue of SAE public
17、ations shall apply.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J1850Class B Data Communication Network InterfaceSAE J1930E/E Systems Diagnostic Terms, Definitions, Abbreviations, and AcronymsSAE J1962Diagnostic ConnectorSAE J1978OBD II Scan ToolSAE
18、 J2012Recommended Format and Messages for Diagnostic Trouble CodesSAE J2186Diagnostic Data Link SecuritySAE J2190Enhanced E/E Diagnostic Test Modes2.1.2 ISO DOCUMENTSAvailable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ISO9141-2:1994(E)Road vehiclesDiagnostic systemsCARB requirements fo
19、r interchange of digitalinformationISO/FDIS 14229:1998(E)Road vehiclesDiagnostic systemsSpecification of diagnostic servicesISO/FDIS14230-3:1997(E)Road vehiclesDiagnostic systemsKeyword Protocol 2000Part 3:ImplementationISO/DIS14230-4Road vehiclesDiagnostic systemsKWP 2000 requirements for Emission-
20、relatedsystems2.1.3 CALIFORNIA ARB DOCUMENTSAvailable from California Air Resources Board, 9528 Telstar Avenue, ElMonte, CA 91731.California Code of Regulations, Title 13, Section 1968.1Malfunction and Diagnostic SystemRequirements1994 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, and
21、 Medium-Duty Vehicles and Engines (OBD II)2.1.4 FEDERAL EPA DOCUMENTSAvailable from the Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.Environmental Protection Agency 40 CFR Part 86Control of Air Pollution From New Motor Vehicles andNew Motor Vehicle Engines; Regul
22、ations Requiring On-Board Diagnostic Systems on 1994 and LaterModel Year Light-Duty Vehicles and Light-Duty Trucks3. DefinitionsMost terms for components and systems contained in this document are included in SAE J1930.This section includes additional definitions of terms not included in SAE J1930.3
23、.1 Absolute Throttle Position SensorThis value is intended to represent the throttle opening. For systemswhere the output is proportional to the input voltage, this value is the percent of maximum input signal. Forsystems where the output is inversely proportional to the input voltage, this value is
24、 100% minus the percent ofmaximum input signal. Throttle position at idle will usually indicate greater than 0%, and throttle position atwide open throttle will usually indicate less than 100%.3.2 BankThe group of cylinders which feed an oxygen sensor. Bank 1 contains the Number 1 cylinder.3.3 Base
25、Fuel ScheduleThe fuel calibration schedule programmed into the Powertrain Control Module orPROM when manufactured or when updated by some off-board source, prior to any learned on-boardcorrection.SAE J1979 Revised SEP97-5-3.4 Calculated Load ValueAn indication of the current airflow divided by peak
26、airflow, where peak airflow iscorrected for altitude, if available. Mass airflow and barometric pressure sensors are not required for thiscalculation. This definition provides a unitless number that is not engine specific, and provides the servicetechnician with an indication of the percent engine c
27、apacity that is being used (with wide open throttle as100%). See Equation 1.(Eq. 1)3.5 Continuous MonitoringSampling at a rate no less than two samples per second.3.6 Fuel TrimFeedback adjustments to the base fuel schedule. Short-term fuel trim refers to dynamic orinstantaneous adjustments. Long-ter
28、m fuel trim refers to much more gradual adjustments to the fuelcalibration schedule than short-term trim adjustments. These long-term adjustments compensate for vehicledifferences and gradual changes that occur over time.4. Technical Requirements4.1 Diagnostic Test Mode General ConditionsThese guide
29、lines are necessary to ensure proper operation ofboth the test equipment and the vehicle during diagnostic procedures. Test equipment, when using messagesdefined in this document, should not affect normal operation of the emission control system.4.1.1 MULTIPLE RESPONSES TO A SINGLE DATA REQUESTThe m
30、essages contained in this document are functionalmessages, which means the off-board test equipment will request data without knowledge of which moduleon the vehicle will respond. In some vehicles, multiple modules may respond with the information requested.In addition, a single module may send mult
31、iple responses to a single request. Any test device requestinginformation must, therefore, have provisions for receiving multiple responses.4.1.2 RESPONSE TIMEFor SAE J1850 network interfaces, the on-board systems should respond to a requestwithin 100 ms of a request or a previous response. With mul
32、tiple responses possible from a single request,this allows as much time as is necessary for all modules to access the data link and transmit theirresponse(s). If there is no response within this time period, the tool can either assume no response will bereceived, or if a response has already been re
33、ceived, that no more responses will be received.For ISO 9141-2 interfaces, response time requirements are specified in the ISO 9141-2 document.For ISO 14230-4 interfaces, response time requirements are specified in the ISO 14230-4 document.4.1.3 MINIMUM TIME BETWEEN REQUESTS FROM SCAN TOOLFor SAE J1
34、850 network interfaces, a tool shouldalways wait for a response from the previous request, or “no response” timeout before sending anotherrequest. In no case should a request be sent less than 100 ms after the previous request.For ISO 9141-2 interfaces, required times between requests are specified
35、in the ISO 9141-2 document.For ISO 14230-4 interfaces, required times between requests are specified in the ISO 14230-4 document.4.1.4 DATA NOT AVAILABLEThere are two conditions for which data is not available. One condition is that the testmode is not supported, and the other is that the test mode
36、is supported, but data is not currently available.For SAE J1850 and ISO 9141-2 interfaces, there will be no reject message to a functional request if therequest is not supported by the module. This prevents responses from all modules that do not support a testmode or a specific data value.For ISO 14
37、230-4 interfaces, there will be a response to every request, either positive (with data) or negative.Format and possible codes of negative responses are given in ISO 14230-4.CLV Current airflowPeak airflow sea level()- Atmospheric pressure sea level()Barometric pressure- 100%=SAE J1979 Revised SEP97
38、-6-Some test modes are supported by a vehicle, but data may not always be available when requested. ForModes $05 and $06, if the test has not been run since test results were last cleared, or for Mode $02 if freezeframe data has not been stored, or for Mode $09 if the engine is running, valid data w
39、ill not be available. Forthese conditions, the manufacturer has the option to either not respond or to respond with data that is invalid.The functional descriptions for these test modes discuss the method to determine if data is valid.4.1.5 MAXIMUM VALUESIf the data value exceeds the maximum value p
40、ossible to be sent, the on-board systemshould send the maximum value possible ($FF or $FFFF). The tool should display the maximum value or anindication of data too high. This is not normally critical for real time diagnostics, but in the case of a misfire at260 km/h with resulting freeze frame data
41、stored, this will be very valuable diagnostic information.4.2 Diagnostic Message Format4.2.1 ADDRESSING METHODFunctional addressing will be used for all generic Diagnostic Test Mode messagesbecause the test tool does not know which system on the vehicle has the information that is needed.4.2.2 MAXIM
42、UM MESSAGE LENGTHSAE J1850 defines required message elements and maximum messagelengths that effectively limit the number of bytes that can be defined by this document to 12 bytes.4.2.3 DIAGNOSTIC MESSAGE FORMATTo conform to the SAE J1850 limitation on message length, diagnosticmessages specified in
43、 this document begin with a three byte header, have a maximum of 7 data bytes,require ERR (error detection byte), and allow RSP (in-frame response byte), as shown in Figure 1.FIGURE 1DIAGNOSTIC MESSAGE FORMATSAE J1979 Revised SEP97-7-4.2.4 HEADER BYTESThe first three bytes of all diagnostic messages
44、 are the header bytes. For SAE J1850 and ISO 9141-2 interfaces, the value of the first header byte is dependent on the bit rate ofthe data link and the type of message, as shown in 4.2.3. The second byte has a value that depends on thetype of message, either a request or a response. For ISO 14230-4
45、interfaces, the value of the first header byte indicates the length of the data field. Thesecond byte is the address of the receiver of the message.The third header byte for all interfaces is the physical address of the device sending the message.Device address $F1 should be used for an OBD II Scan
46、Tool, or any other tool that does not have a specialreason to use another address. Other service tools should use addresses in the range from $F0 to $FD.The response to all request messages in this document will be independent of the address of the testequipment requesting the information.Vehicle ma
47、nufacturers should not use the SAE J1979 header bytes for any purpose other than diagnosticmessages. When they are used, they must conform to this specification.4.2.5 DATA BYTESThe maximum number of data bytes available to be specified in this document is 7. The firstdata byte following the header i
48、s the test mode, and the remaining 6 bytes vary depending on the specifictest mode. For SAE J1850 and ISO 9141-2 interfaces, each unique diagnostic message defined in this document is afixed length, although not all messages are the same length. For modes $01 and $02, message length isdetermined by
49、Parameter Identification (PID). For Mode $05, message length is determined by Test ID. Forother modes, the message length is determined by the mode. This enables the tools to check for propermessage length, and to recognize the end of the message without waiting for possible additional data bytes.For ISO 14230-4 interfaces, the message length is always determin
