J2534 Pass Thru Protocol

A ready-to-deploy J2534 pass-thru protocol for ECU diagnostics

SAE J2534 is a standardized Pass-Thru communication protocol that allows reprogramming and diagnostics of vehicle Electronic Control Units (ECUs) using a universal interface.

It was developed by the Society of Automotive Engineers (SAE) to provide a common way for third-party tools to interact with vehicle ECUs. Its major use-case was flashing new firmware updates or reading and clearing diagnostic data.

Before J2534, OEMs used proprietary tools to update ECUs, making it difficult for independent repair shops and aftermarket tool vendors to access this functionality.

J2534 ensures interoperability between vehicle manufacturers, independent service providers, and hardware vendors.

Embitel offers a ready-to-integrate J2534 stack which is deployable across PC-based as well as hand-held diagnostic tools. We have successfully delivered J2534 pass thru wrapper APIs and J2534 protocol stack with ISO TP layer (ISO 15765) for multiple customers. Our ready solution reduces time-to-market by approximately 12-16 weeks.

Success Story: J2534 Pass thru Implementation

J2534 Pass thru implementation for Telematics Solution

Customer:Automotive Tier-1 focused on telematics and connected mobility.

Challenge: Needed J2534 Pass Thru APIs (.dll) for PC-based ECU flashing and diagnostics.

Solution by Embitel:

Developed a QT C++ .dll with J2534 wrapper API
Integrated ISO TP (ISO15765) stack
Built a CAN-to-USB gateway for ECU communication

Impact:Needed J2534 Pass Thru APIs (.dll) for PC-based ECU flashing and diagnostics.

Tools & Technologies:QT Tool, CANoe, Sample ECU

Development of a J2534 Enabled Vehicle Diagnostic Tool

Customer:Tier-1 automotive firm developing a multi-protocol diagnostic tool.

Challenge:Faced integration and scalability issues while supporting CAN, LIN, and K-Line.

Embitel Solution:

Used J2534 Pass Thru for protocol switching
Enabled ISO 15765, TP 2.0, K-Line communication
Implemented OBDII, UDS, and KWP 2000 protocols

Impact:

Saved 8–10 weeks in development, delivering a scalable, multi-protocol tool.

Tools & Technologies: OBD, PCAN, CANoe

Features of J2534 Pass-thru Protocol

Protocol Switching

Seamlessly supports multiple communication protocols (e.g., CAN, LIN, K-Line).

Hardware Abstraction

Enables hardware-independent communication between ECUs and diagnostic tools.

Customizable

Tailored for use cases like ECU flashing or fault diagnostics and J2534 API integration.

Diagnostic Protocols

Supports OBD-II, UDS (ISO 14229), and KWP 2000 (ISO 14230) for diagnostic applications.

Efficient Data Handling

Manages ISO TP (ISO 15765) for seamless packetized data transmission over CAN.

Platform Compatibility

Works across multiple platforms including Windows.

200+

Customers supported since 2010

100+

Scalable and reusable Bootloader platforms delivered

30%

quicker time-to-market enabled

95%

lesser development time with PC-based automation tools

What We Offer

SAE J2534 protocol stack implementation

Ready-to-integrate pass-thru protocol stack for standardized ECU diagnostics and reprogramming
J2534 API integration
Supports ISO 15765 (ISOTP) and other key automotive communication standards

Development of J2534 pass-thru based Tooling Solution

PC-based and handheld diagnostic tool development with J2534 pass-thru APIs
Supports multiple communication protocols: CAN, LIN, K-Line
Implements key diagnostic standards: UDS (ISO 14229), OBD-II, KWP 2000 (ISO 14230)

J2534 Protocol Software Maintenance and Support Services

Continuous software updates, bug fixes, and compliance enhancements
Ensures compatibility with evolving automotive standards and ECUs

End-to-End ECU Diagnostics Implementation

Development of complete ECU diagnostic software solutions
Includes fault detection, software flashing, and real-time data logging
Scalable for different vehicle architectures and diagnostic tools

A Closer Look at Our SAE J2534 Stack Architecture

Why Embitel

Industry-wide Recognition

We have successfully integrated our J2534 stack into multiple production programs worldwide. Our extensive experience enables us to optimize ECU reprogramming and diagnostics through J2534, ensuring seamless communication between vehicle ECUs and third-party tools.

Configuration & Integration Support

Our J2534 protocol software is designed to be fully configurable as per project specifications.

CMMi Level 3 Certified

As a CMMI level 3 certified organization, we have a robust process model in place. This ensures that the J2534 stack along with other stacks are reliable, bug-free and efficient.

Support & Maintenance

Our J2534 stack integration service comes with a well-defined support and maintenance process. The post-integration support begins as soon as we integrate the J2534 stack with your projects.

FAQs Regarding J2534 Protocol

What are the functions of J2534?

Ans: J2534 serves multiple purposes in vehicle diagnostics and ECU programming, including:

ECU Reprogramming / Flashing
1. Updates ECU firmware to fix bugs, improve vehicle performance, or comply with new emission standards.
2. Used by OEMs, repair shops, and fleet operators for software updates.
Reading and Clearing Diagnostic Trouble Codes (DTCs)
1. Accesses vehicle On-Board Diagnostics (OBD-II) data for troubleshooting.
2. Allows clearing of fault codes after repair.
Real-Time Vehicle Data Monitoring
1. Reads sensor values, system status, and vehicle performance parameters in real time.
Active Tests and Actuator Control
1. Enables testing of individual vehicle components, such as injectors, ABS, or throttle control, by sending commands directly to ECUs.
Security Gateway Access (SGW Authentication)
1. Some modern vehicles have Security Gateways (SGW) that restrict access to certain ECUs. J2534 tools must support authentication mechanisms to unlock access.

What is J2534 pass-thru device?

A J2534 Pass-Thru Device is a Vehicle Communication Interface (VCI) that connects a vehicle’s OBD-II port to a computer running diagnostic or reprogramming software. It acts as a bridge between the ECUs and OEM software using J2534 standards. A typical J2534 pass-thru device consists of:

Hardware Interface: Supports CAN, KWP2000, J1850, etc.
Firmware: Implements J2534 API for communication.
Driver & API Libraries: Allows integration with OEM tools.

Which versions of J2534 standards does your stack support?

Embitel’s J2534 stack supports:

J2534-1 for standard ECU reprogramming.
J2534-2 for extended diagnostics and additional protocol support.
Optional support for DoIP (ISO 13400) and CAN FD for next-gen vehicle architectures.

The stack is designed to be hardware-independent and works with various VCIs.

What is the difference between J2534 and J2534-2?

Feature	J2534 (J2534-1)	J2534-2
Primary Purpose	ECU reprogramming	Extended diagnostics & additional protocols
Protocols Supported	Mandatory protocols for reprogramming	Adds optional protocols (e.g., DoIP, CAN FD)
OEM-Specific Extensions	No	Yes (supports proprietary extensions)
Security Access	Limited	Advanced authentication & security protocols
Support for Additional ECUs	Standard EV powertrain & emission-related ECUs	Covers infotainment system, chassis, body control module

J2534-1 is mandatory for reprogramming in the U.S. due to EPA and CARB regulations, whereas J2534-2 is optional but beneficial for comprehensive vehicle diagnostics.

What is the business model for Embitel’s J2535 stack?

Embitel offers a flexible business model for its J2534 protocol stack, catering to different customer needs. We generally offer our J2534 protocol stack in the library format (.dll) for ease of integration and deployment.

However, if you have specific requirements, we are more than happy to customize our offering to meet your needs.

Do you provide test reports and other documents?

Yes, we do provide all test reports, low-level and high-level documents, MISRA-C report etc.