The Future of SAE J1939 Amid the Expanding Demand for Electric Trucks

Executive Summary

The global shift toward electrification in the commercial vehicle sector, particularly in medium- and heavy-duty trucks, is reshaping automotive communication standards. SAE J1939, the de facto standard for vehicle network communication in diesel-powered commercial vehicles, now faces a new challenge—and opportunity—as electric trucks become more prominent. This report explores how SAE J1939 is adapting to support the rapidly evolving electric truck market, the ongoing developments within the standard, potential limitations, and complementary or alternative protocols that may emerge.

1. Introduction: SAE J1939 in Traditional Vehicles

SAE J1939 is a higher-layer protocol based on CAN (Controller Area Network) and is widely used in the commercial vehicle industry for communication and diagnostics. Originally developed to serve internal combustion engine (ICE) vehicles, J1939 provides a common language for electronic control units (ECUs), such as the engine control module (ECM), transmission control module (TCM), and braking systems.

Key characteristics:

Based on CAN (ISO 11898) with 250 kbps or 500 kbps data rate.
Uses 29-bit identifiers with predefined Parameter Group Numbers (PGNs).
Provides support for diagnostics (DMs), address claiming, and transport protocols.

2. Growth of Electric Trucks: Market Trends

2.1. Drivers of Electrification

Environmental regulations targeting greenhouse gas reduction.
Lower total cost of ownership due to reduced fuel and maintenance costs.
Government incentives and clean vehicle mandates.
Technological advancements in battery energy density and thermal management.

2.2. Market Growth

The electric truck market is projected to grow at a CAGR of over 25% between 2023 and 2030. Major OEMs like Volvo, Daimler Truck, Tesla, and BYD are accelerating development in medium and heavy-duty electric trucks.

3. Challenges for SAE J1939 in Electric Trucks

Although robust and reliable, SAE J1939 was not originally designed with electrification in mind. Transitioning to electric trucks introduces new system requirements and components that strain or fall outside the standard’s scope:

3.1. New Powertrain Architecture

Absence of a traditional ECM.
Introduction of new ECUs for battery management systems (BMS), traction inverters, and DC-DC converters.

3.2. High-Speed Communication Demands

Fast and reliable data exchange is needed between high-voltage components and control systems.
Classical CAN may not meet bandwidth requirements for high-resolution diagnostics and control.

3.3. Limitations of Classical CAN

Max 1 Mbps (for Classical CAN) or 8 Mbps (for CAN FD).
Limited payload of 8 bytes in Classical CAN (up to 64 bytes with CAN FD).
Increasing network congestion as node count rises.

4. Evolving SAE J1939 Standards

The SAE Truck and Bus Control and Communications Network Committee has been actively updating J1939 to address modern vehicle needs:

4.1. SAE J1939-22: Support for CAN FD

Released in 2022, this revision adds support for CAN FD.
Increases payload from 8 bytes to 64 bytes per frame.
Enables higher data rates up to 8 Mbps.
Improves efficiency of diagnostics and event-based messaging.

4.2. SAE J1939-23: Battery Electric Vehicle (BEV) Additions

Introduces PGNs specifically for electric powertrain components.
Defines parameters for high-voltage battery packs, motor controllers, state-of-charge (SoC), and energy consumption.
Enables interoperability across different OEMs and component suppliers.

4.3. Other Relevant Updates

J1939-84: Emission-related OBD compliance testing now includes electric powertrains.
J1939-91 series: Enhanced network management, security, and diagnostics.

5. Future Outlook for J1939 in Electric Vehicles

5.1. Integration Rather Than Replacement

SAE J1939 is unlikely to be replaced outright. Instead, its evolution (e.g., via J1939-22 and J1939-23) will enable integration with new technologies in electric trucks.

Examples:

Using J1939-22 on CAN FD for backbone communication.
Integrating J1939 with other high-speed protocols like Automotive Ethernet (for ADAS, cameras).
Employing J1939 as a subnetwork alongside unified diagnostics and gateway architectures.

5.2. Transition to Multi-Protocol Architectures

Electric trucks will likely use hybrid networking stacks, including:

CAN/CAN FD (J1939)
Automotive Ethernet (100/1000BASE-T1)
LIN (for simple actuators and switches)
Wireless protocols for predictive maintenance and remote diagnostics

Gateways will ensure seamless communication between subsystems, translating J1939 messages as needed.

5.3. Security Considerations

Electric trucks bring cybersecurity concerns, especially due to increased software content and telematics. SAE J1939-91C introduces secure messaging, but additional work is needed for end-to-end encryption and authentication in EV networks.

6. Competitors and Complementary Technologies

6.1. Automotive Ethernet

Higher bandwidth, up to 10 Gbps.
IP-based communication and support for TSN (Time-Sensitive Networking).
Suited for data-heavy applications (e.g., over-the-air updates, real-time video, sensor fusion).
Potential to supersede J1939 in select functions, but not a direct competitor for deterministic control.

6.2. OneNet (NMEA 2000’s IP-Based Successor)

Developed for the marine industry but relevant for EVs with similar needs for bandwidth and interoperability.
Based on IPv6 and Ethernet; enables seamless internet-style communication.

6.3. Unified Diagnostic Services (UDS, ISO 14229)

Used for advanced diagnostics over CAN and Ethernet.
Complements J1939 by providing OEM-specific diagnostic capabilities.

7. Opportunities for Industry Players

Suppliers, OEMs, and tool vendors can capitalize on the evolving J1939 ecosystem:

Tooling and simulators that support J1939-22 and electric PGNs.
Gateways and bridges for CAN FD-to-Ethernet integration.
Software stacks enabling secure J1939 communication.
Training and documentation tailored to engineers transitioning from ICE to EV design.

Conclusion

The future of SAE J1939 is not defined by obsolescence but by adaptation. As electric trucks become mainstream, the standard is evolving to accommodate new components, higher communication speeds, and modern diagnostics. The introduction of J1939-22 and J1939-23 marks a significant step forward, ensuring that J1939 remains relevant and vital in electric vehicle network architectures. Though complementary technologies like Automotive Ethernet will play an increasing role, SAE J1939’s robustness, widespread adoption, and industry support will sustain its presence well into the electric era.

Automotive Ethernet: The Definitive Guide

Ethernet, the world’s most widely used local area networking technology, has expanded beyond traditional IT environments and into the heart of modern vehicles. As the number and complexity of electronic systems in cars continue to increase, Automotive Ethernet has emerged as a powerful and versatile solution for in-vehicle communication.
Automotive Ethernet – The Definitive Guide offers a comprehensive exploration of the technology, detailing the physical layers, protocols, and standards that enable high-speed, reliable data transmission in automotive environments.

Topics Covered

This extensive guide covers a wide range of essential topics, including:

Automotive electromagnetic, environmental, and electrical requirements.
Networking fundamentals and the OSI Reference Model.
Structure and working groups within IEEE Project 802.
The IEEE 802.3 (Ethernet) Physical Layer and Media Access Control.
A detailed look at physical layer technologies such as 100BASE-T1, 1000BASE-T1, MultiGBASE-T1, 10BASE-T1S, and others.
MAC addressing, Ethernet frame formats, and hardware device interfaces.
Comparisons between Ethernet and legacy automotive networks like CAN, CAN FD, LIN, MOST, and FlexRay.
The TCP/IP protocol suite, including IPv4/IPv6, ICMP, ARP, NAT, TCP, UDP, Diagnostics over IP (DoIP), and SOME/IP.
The Audio Video Bridging (AVB) / Time-Sensitive Networking (TSN) standards that enable real-time media transport over Ethernet, including:
- SRP (IEEE 802.1Qat)
- FQTSS (IEEE 802.1Qav)
- gPTP (IEEE 802.1AS)
- AVTP (IEEE 1722)

The book also examines how diagnostics, measurement, and calibration differ in an Ethernet-based vehicle network, with an overview of available MCD (Measurement, Calibration, Diagnostics) tools.

Intended Audience

This guide is ideal for:

Electronics engineers, communication engineers, testers, and technicians involved in the development of automotive electronics. If you currently work with CAN, LIN, FlexRay, MOST, or similar automotive networks, this book will expand your knowledge and future-proof your skills.
Ethernet hardware designers and network application developers seeking insight into Automotive Ethernet’s unique requirements and implementations.
Software developers working on Android, Linux, iOS, or Windows systems, particularly those building apps or systems for connected vehicles.
University students and trainees in electrical engineering, embedded systems, or automotive technologies looking to gain foundational and applied knowledge in this evolving domain.

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