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SURFACE VEHICLE 400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDED PRACTICE J1978REV.APR2002Issued 1992-03
Revid
2002-04Superding J1978 FEB1998
OBD II Scan Tool — Equivalent to ISO/DIS 15031-4:December 14, 2001
This document superdes SAE J1978 FEB1998, and is technically equivalent to ISO/DIS 15031-4:December 14,2001, except for minor reorganization of Paragraphs 1 and 2.
Foreword—On-Board Diagnostic (OBD) regulations require pasnger cars, and light and medium duty trucks, to support communication of a minimum t of diagnostic information with off-board “generic” test equipment. This document describes the minimum capabilities that must be supported by test equipment (e.g., handheld scan tools, PC bad diagnostic computers, etc.) that are intended to communicate with an OBD compliant vehicle to retrieve the OBD information.
SAE J1978 was originally developed to meet U.S. OBD requirements for 1996 and later model year vehicles. ISO 15031-4 was bad on SAE J1978 and was intended to meet European OBD requirements for 2000 and later model year vehicles, and added the capability to communicate on an ISO 15765-4 rial data link. This document is technically equivalent to ISO 15031-4 with U.S. specific requirements identified.
TABLE OF CONTENTS
1.
<31.1
<31.2
Differences from ISO Document (32)
<32.1
Applicable Publications ............................................................................................................................32.1.1
32.1.2
.42.2
42.2.1
43.
Terms 44.
Required Functions of the External 45.
.46.Connections to the Vehicle.. (5)
7.Network Access (5)
7.1Automatic Determination of Communication Interface (5)
7.2Handling of No Respon from the Vehicle (7)
7.3Handling of Multiple Respons from the Vehicle (7)
7.4Message Structure (7)
7.5Diagnostic Trouble Codes Monitoring (7)
7.6Obtain and Display OBD Emissions Related Current Data, Freeze Frame Data,
and Test Parameters and Results (7)
7.7Code Clearing (8)
7.8On-Board Diagnostic Evaluations (8)
7.8.1Completed On-Board System Readiness Tests (8)
7.8.2Supported On-Board System Readiness Tests (8)
7.8.3Malfunction Indicator Lamp - Status and Control (8)
7.9U of StopCommunication Service Associated with ISO 14230-4 (optional) (8)
8.Ur Interface (8)
8.1Display (8)
8.2Ur Input (9)
9.Power Requirements (9)
9.1Vehicle Battery Voltage (9)
9.1.1Vehicle Battery Voltage for 12 V DC only (9)
9.1.2Vehicle Battery Voltage for 12 V DC and 24 V DC (9)
9.2Vehicle Battery Current Consumption (10)
10Electromagnetic Compatibility (EMC) (10)
11Conformance Testing (10)
11.1General (10)
11.2Determine OBD Communication Type (11)
11.3On-Board System Readiness Test (12)
11.4Select Functions (12)
11.5Select and Display Items (12)
11.6Confirm Requests to Clear Codes (13)
11.7General Diagnostic Communication Tests (13)
11.8Capacitance and Impedance at the Diagnostic Connector (13)
11.9Operating Voltage and Current Requirement (13)
11.10Protocol Check (13)
11.11Alphanumeric Display (14)
11.12Ur Manual and Help Facility (14)
12Notes (14)
12.1Marginal Indicia (14)
1.Scope
1.1Purpo—This SAE Recommended Practice superdes SAE J1978 FEB1998, and is technically equivalent
to ISO/DIS 15031-4:December 14, 2001.
This document is intended to satisfy the requirements of an OBD scan tool as required by U.S. On-Board Diagnostic (OBD) regulations.
The document specifies:
a. A means of establishing communications between an OBD-equipped vehicle and external test
equipment,新型工业化道路
b. A t of diagnostic rvices to be provided by the external test equipment in order to exerci the
rvices defined in SAE J1979,
赵胜c.Conformance criteria for the external test equipment.
1.2Differences from ISO Document—The ISO 15031-4 document is intended to satisfy the requirem
ents of
OBD requirements in countries other than the U.S., and includes functionality not required or not allowed in the U.S.
Notable exceptions are:
a.Propod U.S. OBD regulations will allow ISO 15765-4 as an allowable OBD rial data link at
500 kbps only. Only tho provisions of ISO 15765-4 that pertain to 500 kbps are required to be
supported by an SAE J1978 diagnostic scan tool.
b.Propod U.S. OBD regulations will not allow greater than 20 V at the SAE J1962 connector. Only the
3d绘画教程Type A connector as defined in SAE J1962 needs to be supported by an SAE J1978 diagnostic scan
tool.
Differences between the documents are highlighted in the technical requirements ctions of this do
cument.
Deleted text is highlighted with struck through and new text is highlighted with bold italic.
NOTE—To maintain equivalency of the documents, a comma is ud as a decimal marker for numeric values in this document.
2.References
2.1Applicable Publications—The following publications form a part of this specification to the extent specified
herein. Unless otherwi indicated, the latest version of SAE publications shall apply.
2.1.1SAE P UBLICATIO NS—Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.
SAE J1850 MAY2001—Class B Data Communications Network Interface.
SAE J1930—Electrical/Electronic Systems Diagnostic Terms, Definitions, Abbreviations, and Acronyms -Equivalent to ISO/TR 15031-2:April 30, 2002
SAE J1962—Diagnostic Connector - Equivalent to ISO/DIS 15031-3: December 14, 2001
SAE J1979—E/E Diagnostic Test Modes - Equivalent to ISO/DIS 15031-5:April 30, 2002
SAE J2012—Diagnostic Trouble Code Definitions - Equivalent to ISO/DIS 15031-6:April 30, 2002
2.1.2ISO P UBLICATIONS—Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002.
ISO 7637-1:1990—Road vehicles — Electrical disturbance by conduction and coupling — Part 1: Pasnger cars and light commercial vehicles with nominal 12V supply voltage — Electrical transient
conduction along supply lines only
ISO 9141-2:1994—Road vehicles — Diagnostic systems — Part 2: CARB requirements for interchange of digital information
ISO 9141-2:1994/Amd.1:1996—Road vehicles - Diagnostic systems — Part 2: CARB requirements for interchange of digital information Amendment 1.
ISO 14230-4:2000—Road vehicles — Keyword protocol 2000 for diagnostic systems — Part 4: Requirements for emission-related systems
ISO/DIS 15031-4: December 14, 2001—Road vehicles — Communication between vehicle and external test equipment for emissions-related diagnostics — Part 4: External test equipment
郁闷的近义词ISO 15765-4:2001—Road vehicles — Diagnostics on Controller Area Network (CAN) – Part 4: Requirements for emissions-related systems
ISO 16750-2—Road vehicles — Environmental conditions and testing for electrical and electronic equipment — Part 2: Electrical loads
2.2Related Publication—The following publication is provided for information purpos only and is not a required
part of this specification.
2.2.1ISO P UBLICATION—Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002.
ISO 15031-1:2001—Road vehicles — Communication between vehicle and external test equipment for emissions-related diagnostics — Part 1: General information
3.Terms and Definitions—For the purpo of this document the definitions of SAE J1930 apply.
4.Required Functions of the External Test Equipment—The following are the basic functions that the
external test equipment is required to support or provide:
—Automatic hands-off determination of the communication interface ud to provide OBD rvices on the vehicle,
—Obtaining and displaying the status and results of vehicle on-board diagnostic evaluations,
—Obtaining and displaying OBD emissions related diagnostic trouble codes (DTCs),
—Obtaining and displaying OBD emissions related current data,
—Obtaining and displaying OBD emissions related freeze frame data,
—Clearing the storage of OBD emissions related diagnostic trouble codes, OBD emissions related freeze frame data storage and OBD emissions related diagnostic tests status,
—Obtaining and displaying OBD emissions related test parameters and results as described in SAE 促销活动有哪些
J1979,
—Provide a ur manual and/or help facility.
5.Communication Protocols—The following communication protocols shall be supported:
a.ISO 9141-2
四个合格党员
The following specifications clarify and, if in conflict with ISO 9141-2, override any related
specifications in ISO 9141-2:
— The maximum sink current to be supported by the external test equipment is 100 mA,
— The range for all tests performed relative to ISO 7637-1 is –1.0 to +40.0 V,
— The minimum bus idle period before the external test equipment shall transmit an address, shall be 300 ms.
b.SAE J1850 41,6 kbps PWM (pul width modulation)
c.SAE J1850 10,4 kbps VPW (variable pul width)
d.ISO 14230-4 (Keyword protocol 2000)
e.ISO 15765-4 (CAN)
— NOTE: Propod U.S. regulations will allow ISO 15765-4 as an allowable OBD rial data link at 500Kbps only. Only tho provisions of ISO 15765-4 that pertain to 500 kbps are
required to be supported by an SAE J1978 diagnostic scan tool.
A fully compliant external test equipment shall support all communication protocols as specified in Section 5.
Only one protocol is allowed to be ud in any one vehicle to access all legislated emission-related functions.
The external test equipment is not required to support simultaneous u of protocols.附和的读音
6.Connections to the Vehicle
NOTE—Propod U.S. regulations will not allow greater than 20 V at the SAE J1962 connector. Only the Type A connector as defined in SAE J1962 needs to be supported by an SAE J1978
diagnostic scan tool.
Connection to the vehicle shall be made using the connector specified in SAE J1962. All data transfer between external test equipment and the vehicle shall conform to the requirements of SAE J1979.
7.Network Access
7.1Automatic Determination of Communication Interface—The external test equipment shall have an
“Automatic hands-off determination of the communication interface” built in to determine the communication protocol ud in a given vehicle.
The tests to determine the communication interface and protocol may be performed in any order and, where possible, may be performed simultaneously. The specified quence for each test shall be ud to determine the interface to be ud to access OBD rvices on a vehicle:
a.The electrical interface in the external test equipment for the manufacturer discretionary contact
assignments shall be effectively open circuit as a default condition or state whilst this procedure is
being performed.
b.The equipment shall inform the ur that initialization is occurring.
c.The equipment shall, using only the following tests, attempt to determine the OBD communications
protocol ud by the vehicle. No ur intervention is allowed during this stage.
元稹读音1.Test for SAE J1850 41,6 kbps (kilobits per cond) PWM (pul width modulation):
—enable the SAE J1850 41,6 kbps PWM interface;
—nd a rvice $01 PID $00 request message;
—if a rvice $01 PID $00 respon message is received then SAE J1850 41,6 kbps PWM is the vehicle's OBD protocol.
2.Test for SAE J1850 10,4 kbps VPW (variable pul width):
—enable the SAE J1850 10,4 kbps VPW interface;
—nd a rvice $01 PID $00 request message;
—if a rvice $01 PID $00 respon message is received then SAE J1850 10,4 kbps VPW is the vehicle's OBD protocol.
