SAE J2534
For access to SAE J2534 information go to the service information website, www.techauthority.com.
SAE J2534 pass-thru tools and software calibrations are found in the Related Documents link at the bottom of the www.techauthority.com homepage. For complete information covering FCA's J2534 product, refer to the J2534 Manual 3.3.
The J2534 flash application can be downloaded from TechAuthority. Note that it includes a separate application for 2009 and prior model years (for emission modules only) and a newer application (wiTECH Diagnostic System) supporting 2010 and newer model years.
A J2534 pass-thru device, such as the Launch Tech J-Box, connects the. Reprogramming is software based, so it can be a more challenging.
The wiTECH 2.0 application is a cloud-based diagnostic system with enhanced security and requires an additional subscription to TechAuthority resources. Note that FCA's own MicroPod II is a SAE J2534-compliant device but compatibility with the new security features of wiTECH 2.0 requires an upgraded MicroPod II with a serial number of WSP-31560 or higher. .
Note: Older MicroPod II units (before serial number WSP-31560) will not communicate with the wiTECH 2.0 programming application but will communicate with wiTECH 1.0. However, wiTECH 1.0 will be discontinued in late 2017 and not supported.
FCA recommends the newer MicroPod II as the vehicle communications interface but aftermarket device manufacturers are known to be developing wiTECH 2.0-compatible J2534 devices. Techs are warned to confirm that compatibility with their device manufacturer prior to use.
The TechAuthority website provides access to TechAuthority Online with a purchased subscription. The subscription allows access to the SAE J2534 Application, SAE J2534 applicable ECU flash files, Technical Service Bulletins (TSBs), service diagnostic procedures, and Chrysler wiring diagrams.
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Which models and model years of vehicles can be reprogrammed?
The wiTECH 2.0 (SAE J2534) application will do both emission and non-emission diagnostics and programming for all 2018 and newer models with limited coverage on earlier models. For a list of models and model years programmable using wiTECH 2.0, view the reference chart under TechAuthority.com 'RELATED DOCUMENTS.' Navigate to the DCCTools Knowledgebase and find the 'Supported Vehicles' (pdf) document clicking through the left-side menu into the 'Chrysler J2534 Application' folder. Also:
- Some 1995 and newer OBDII vehicles can use the J2534 flash application for emission-related modules only.
- Emission related functions for engine and transmission control modules can also be reprogrammed with Chrysler's diagnostic scan tools.
- Powertrain Control Module Initialization requires the use of Chrysler's diagnostic scan tools.
- Specific body control modules can be reprogrammed with Chrysler's diagnostic scan tools.
How does a technician determine whether a reprogramming event is needed for a particular vehicle?
- Launch www.techauthority.com.
- On bottom of home page, click on “Related Documents and Links” and a new page will load.
- Inside the “Related Documents” section of the page, click on “Flash Availability - J2534/Pass Thru Device” to view the PDF document that contains a list of supported calibration files. The PDF contains the old and new calibration part numbers, along with the corresponding TSBs that can either be opened from the server, or saved to the user’s hard-disk drive, then opened. This requires a PDF viewer to view Chrysler’s file.
What OEM equipment is available to reprogram vehicles?
For information about FCA diagnostic scan tools go to www.techauthority.com, on bottom of main page, click “Related Documents and Links”. On the left side of the page click on “wiTECH Order Form' to purchase FCA's OEM diagnostic scan tool. Additional information is available at www.fcawitech.com/aftermarket.
For older, non-CAN FCA vehicles a DRB III is available at www.controllertech.com/drb-iii-emulator.html.
For a list of Chrysler recommended SAE J2534 tools refer to page 4 of the J2534 Manual 3.3.
How does a technician obtain the Calibration?
To download SAE J2534 ECU Flash reprogramming files, you will need a valid TechAuthority Online Subscription.
After logging into TechAuthority Online, select J2534 Flash Application Process link. On the new window, scroll to the section labeled “The Chrysler J2534 Flash Application – Application Usage and Support”. Select 'J2534 Flash Availability.'
To download flash files, select the “Click here to download ECU reprogramming files” link. Refer to the J2534 Manual 3.3 for complete information.
Identify computer system requirements needed to support reprogramming.
Review the minimum PC Requirements found on link from Related Documents at bottom of www.techauthority.com main page.
7/24/2017
Introduction
J2534 is a concept that enables flash programming of an emission related ECU regardless of the communication protocol that is used by the ECU. The purpose is that only one tool (hardware device), often referred to as the pass-thru device, should be needed for all kind of ECUs. The connection between the J2534 device and the ECU is a SAE J1962 connector. The J2534 hardware device is to be connected to a standard PC which holds the Application Program Interface (API) from the vehicle manufacturer (Figure 1). The connection between the PC and the J2534 hardware device is up to the manufacturer of the tool, but USB is probably the most common. A J2534 API DLL is provided from the hardware tool developer which handles the communication to the PC. The J2534 document withholds requirements for the hardware and software of a J2534 tool. The communication protocols supported are; ISO9141, ISO14230 (KWP2000), J1850, CAN (ISO11898), ISO15765 and SAE J2610. In 2005 J1939 was also included.
Figure 1. J2534 setup.
Background
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Vehicles become more and more complex and almost every function is controlled by an Electronic Control Unit (ECU). The ECUs are often connected onto a communication bus to be able to share data between each other. The most common protocol is CAN, but there are other protocols. There are many Vehicle manufactures and almost as many different communication protocols. Every vehicle manufacturer has a tool for analyzing and reprogramming their product, and this tool is often expensive. This makes it difficult for a car, bus or truck workshop to analyze and repair all kind of vehicles.
U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (ARB) have been trying to get vehicle manufactures to support common emission-related services for the aftermarket. The Society of Automotive Engineers (SAE) created the J2534 standard, in 2002, to promote the EPA and ARB in their work.
Hardware Requirements
The J2534 hardware works like a gateway between the vehicle ECU and the PC. This pass-thru device translates messages sent from the PC into messages of the protocol being used in the vehicle ECU. J2534 supports the following protocols:
- J1939 (since 2005)
The connection between the PC and the J2534 hardware can freely chosen by the manufacturer of the device i.e. RS-232, USB or maybe a wireless interface. The vehicle manufacturers programming application is not dependant on the hardware connection. Therefore any device can be used for programming any vehicle regardless of the manufacturer.
The connection between the J2534 hardware and the vehicle should be the SAE J1962 connector, also called the OBDII connector. The maximum length of the cable between the J2534 device and the vehicle is 5 meters. If the vehicle manufacturer doesn’t use the J1962 connector, necessary information for connection has to be provided.
The J2534 hardware interface should be able to provide a supply voltage between 5 and 20 volts to the J1962 connector. The power supply should use one of the pins 6, 9, 11, 12, 13 or 14 of the connector and this choice should be selectable in the software. The maximum source current is 200mA and the settling time should be within 1ms.
The J2534 hardware interface should have enough memory to buffer 4Kb of transmit messages and 4Kb of received messages. And the processor must naturally be fast enough to process all messages so that no messages are lost.
Software Requirements
Programming of an emission related ECU using J2534 is done from a PC, preferably a laptop computer, with a Win32 operating system (Windows 95 or later).
Each vehicle manufacturer will have an own API software used for analyzing and programming of their vehicles. If their vehicles only use i.e. ISO 9141, no other protocols have to be supported by the application. It is important that this application conform to the functions in the J2534 API.
This application will have complete information of the ECUs that are supported by the application. This application also includes a user interface where choices can be made depending on the ECU and what action to perform.
A vehicle repair workshop that wants to analyze and re-program vehicles from different manufactures must have an API for each. This API can be downloaded from the internet or installed from a CD or DVD. How this API is provided depend on the manufacturer, but they do charge the customer (repair workshop) ordering it. The price differs a lot between manufacturers, a one year subscription costs between $75 and $2500.
Each manufacturer of a J2534 tool (hardware device) must have a DLL-file which includes functions and routines for communicating with the PC. The DLL-file is then loaded into the vehicle manufacturer’s application. The functions in the J2534 tool are linked to a corresponding function in the application. The DLL-file also includes routines for the connection (RS-232, USB etc.) between the J2534 tool and the PC.
The intention is that every J2534 tool should to be capable of communicating with all protocols supported by the J2534 standard. The application provided by the vehicle manufacturers use commands described in J2534 standard to connect to a hardware tool (of any brand). The connection and initialization gives the hardware tool information of which protocol that is used. Thereafter it is up to the hardware tool to manage the connection to the vehicle with de desired protocol. The PC application will send messages in the earlier determined protocol format to the hardware tool which buffers the messages and transmits the messages in the order they were received.
J2534 Application Programming Interface (API)
The J2534 API consists of a number of functions for communication which must be supported by both hardware tool and vehicle manufacturer application. For the PC application developer this means that all commands and messages must made with the functions defined in the API. See table 1 below.
Function | Description |
PassThruConnect | Establish a connection with a protocol channel. |
PassThruDisconnect | Terminate a connection with a protocol channel. |
PassThruReadMsgs | Read message(s) from a protocol channel. |
PassThruWriteMsgs | Write message(s) to a protocol channel. |
PassThruStartPeriodicMsg | Start sending a message at a specified time interval on a protocol channel. |
PassThruStopPeriodicMsg | Stop a periodic message. |
PassThruStartMsgFilter | Start filtering incoming messages on a protocol channel. |
PassThruStopMsgFilter | Stops filtering incoming messages on a protocol channel. |
PassThruSetProgrammingVoltage | Set a programming voltage on a specific pin. |
PassThruReadVersion | Reads the version information for the DLL and API. |
PassThruGetLastError | Gets the text description of the last error. |
PassThruIoctl | General I/O control functions for reading and writing protocol configuration parameters (e.g. initialization, baud rates, programming voltages, etc.). |
J2534 function description.
The first command that is sent is the PassThruConnect which establish the connection between the PC application and the J2534 hardware tool. This command includes information about which protocol to use, standard or extended CAN identifier or if ISO15765 is used. The command also includes a channel identification which will be used for all following communication. If the connection was successful, a STATUS_NOERROR value is returned, which indicates that the function has been successfully performed. Before any messages can be sent an initialization has to be made, PassThruIoctl, where parameters like node address, baud rate or protocol specific parameters are set.
All messages sent from the PC application follow the same structure which consists of: protocol type (i.e. J1850, CAN, J9141), receive message status, transmit message flags, received message timestamp (microseconds), data size in bytes, extra data index (start position of extra data in received message i.e. IFR, CRC, checksum), and last but not least an array of data bytes (the received message). It is possible to send CAN messages longer than 8 bytes using ISO15765 commands if this feature was selected upon connection.
Some ECUs sends a lot of messages with short period of time between each message. The filter function, PassThruStartMsgFilter, can be set to either block or pass messages. This will decrease the messages needed to be sent between the hardware tool and the PC. The message is first “ANDed” with a mask which gives the opportunity to compare only some important bits of the identifier. Thereafter the “ANDed” message is compared to a specific pattern.
J2534 API DLL
The J2534 API DLL provides a linkage between the API functions and the hardware tool. Since the PC application should not have to care about which communication protocol is being used between the PC and the hardware tool. Each manufacturer of a hardware tool has a DLL-file with a unique name. This way it is possible for the software application on the PC to distinguish which hardware tool to connect. It is important that the developer of the firmware in the hardware tool follows the API and name the functions exactly as in the J2534 description. Otherwise it will be impossible for the PC application to find the functions in the DLL when performing the linkage.
Source: https://www.kvaser.com/about-can/can-standards/j2534/