Updated on April 15, 2025
The world of construction technology is filled with acronyms: IoT, MRO, ERP, ELD, RFID, BLE, and the list goes on. But there are three acronyms that are critical in helping us understand the data we can get from vehicles and equipment: OBD, JBUS, and CAN bus.
In this blog, we’ll walk through what makes CAN bus, JBUS and OBD different and the benefits of using CAN for equipment and fleet management.
What’s the difference between OBD, JBUS, and CAN bus?
CAN bus, OBD, and JBUS all involve ways for sensors and systems used in automobiles and equipment to detect and communicate data. However, each has distinct differences and applications.
CAN (Controller Area Network) or CAN bus
The CAN bus is a common communication system. It lets different electronic control units (ECUs) in a vehicle or equipment talk to each other. A network protocol helps different systems share data. This includes the engine, transmission, brakes, sensors, and more.
CAN bus enables real-time, reliable and robust communication, making it suitable for applications requiring extensive data coverage and integration between different machine components. The CAN specification enables developers to implement various protocol speeds. Newer vehicles typically implement faster versions of the protocol.
The CAN bus in vehicles and equipment is often available for diagnostic testing. It allows for data monitoring and collection through a special connector.
The Bottomline
CAN is the underlying network used to allow various systems within vehicles and equipment to communicate with each other.
OBD (On-Board Diagnostics)
OBD, or OBD-II, is a required and standard diagnostic system. Most cars sold in the US since 1996 use it. It provides a standardized way for diagnostic equipment to access and retrieve information from the vehicle's ECUs.
OBD-II mainly focuses on diagnostic functions. It gives access to data about emissions, engine performance, and vehicle sensors. It is often used for emissions testing and vehicle diagnostics. It helps retrieve fault codes and connect devices like GPS locators and dash cameras.
The most deployed implementation of OBD is specified in ISO 15765-4.
The Bottomline
OBD-II defines the interface and protocols for diagnostics and emissions. It is mainly used in cars and light trucks.
JBUS (J1939)
JBUS, also called J1939, is a special protocol and standard. It works on top of the CAN bus physical layer. Manufacturers primarily use it in heavy-duty commercial vehicles, such as trucks, buses, and construction equipment.
J1939 defines a standard set of messages and parameter definitions for communication between ECUs in these vehicles. It can also be found on equipment like air compressors and generators. It allows for standardized data exchange related to vehicle control, diagnostics and monitoring.
J1939 is designed to meet the specific requirements of the heavy-duty vehicle industry.
The Bottomline
J1939 is an application layer protocol, and interface definition, specific to heavy-duty commercial vehicles.
What are the benefits of using CAN?
In equipment and fleet management, CAN bus offers several benefits.
Data Coverage
CAN bus provides access to a wide range of data. It allows the gathering of real-time data from different vehicle systems. This includes the engine, transmission, brakes, sensors, and more.
This extensive data coverage allows for a more detailed analysis of performance, fuel consumption, driver behavior, and other relevant metrics.
CAN bus trackers in J1939 systems can collect many data points. This includes advanced diagnostics for engine performance and faults, beyond standard OBD-II parameters.
Data Granularity
J1939 CAN bus offers a greater degree of granularity in terms of data resolution and spans a much wider range of parameters. It gives access to many individual sensor readings and system parameters. This occurs when the vehicle's OEM (original equipment manufacturer) uses the ECU over the CAN bus.
This detailed information is very useful for fleet managers who need a wider range of data to improve operations and spot potential problems.
Customization and Flexibility of Data Types
CAN bus supports a rich and varied set of data types, including numeric, text, and status information. It also allows users to prioritize messages, enabling them to transmit critical data with higher precedence.
The CAN bus collects many data points. These points relate to performance, maintenance, fuel, idle time, and other important needs.
This robust set of data allows your asset management team to be more proactive and have greater information for decision-making purposes, speeding up your time to repair and ultimately maximizing the uptime on your equipment.
Scalability of Network
CAN bus is designed to support many interconnected devices thanks to its networked topology.
CAN bus supports multi-node communication, allowing for easy expansion of the network by adding new nodes or devices. It follows a distributed architecture, where each node can send and receive messages independently.
Integration and Interoperability Between Systems
The CAN bus protocol is relatively simple compared to other network protocols. Its message-based communication model, with standardized message frames, facilitates easy integration and interoperability between different devices and systems.
Data Reliability
CAN bus is a robust and reliable communication protocol in wide use across multiple industries. It operates on a dedicated bus, separate from other vehicle systems, ensuring data integrity and minimizing interference. CAN bus is designed to operate in harsh and noisy environments.
It uses a differential signaling scheme, which ensures reliable data transmission even in the presence of electromagnetic interference (EMI) and other disturbances.
Which CAN bus Protocol Should You Choose?
So, can CAN bus be used for vehicles and equipment? The short answer is yes. While it is most associated with vehicular systems, CAN bus is a versatile communication protocol suitable for many types of equipment and fleet needs.
CAN bus is widely employed in automotive applications, industrial automation, and other domains. Taking advantage of the rich data set provided by both of the protocols described in this article can add value to your equipment and fleet management programs.
Tenna’s TennaCANbus tracker is a premier solution for contractors who want to go beyond location, utilization and maintenance tracking to monitor idle time, fuel consumption, engine information, fault codes, battery level, environmental data and more.
The tracker also makes it possible to track external power take-off (PTO). External PTO is often used to power external accessories, including hydraulic pumps, generators, compressors and other types of equipment that require mechanical or electrical power to operate.
This game-changing tracker enables contractors to understand more about how their equipment is being used, including when PTO is engaged, which simplifies compliance reporting and improves the accuracy of distribution costs.
To learn more about what CAN bus data can offer your business or for a detailed look at Tenna's CAN bus tracker, contact us.
Frequently Asked Questions About CAN bus, JBUS, and OBD
What is the difference between JBUS and OBD?
OBD is an older protocol than J1939 and was initially targeted at passenger cars. The querying device sends a limited set of parameters called PIDs on demand. Many of these data sources are 8 bit.
OBD suits the needs for which developers originally created it: emissions diagnostic testing. OBD offers 10 service modes that allow for parameter monitoring and Diagnostic Trouble Code reading and resetting.
Service 01 is often used in telematics. It offers around 200 PIDs that provide real-time data. However, most people do not use these in actual vehicles. More recent implementations on newer vehicles have expanded the number of PIDs to yield more data types, which allow expanded performance monitoring and diagnostics. Many trucks today (e.g., Macks) use OBD.
J1939 provides a larger set of data types. These types are shared using SPNs, which stand for Suspect Parameter Numbers. J1939 defines over 500,000 SPNs. These SPNs identify specific parameters within the transmitted data.
Data like RPM, wheel speed, and Diesel Particulate Filter status are available. This includes hundreds of thousands of other real-time data points, depending on the vehicle or equipment manufacturer. J1939 is the most complete source of diagnostic, monitoring, and maintenance data available widely.
As with OBD, specific data types are only available if the equipment or vehicle manufacture implemented reporting of that data over the CAN bus. One truck may report 30 different parameters. Another truck might only report RPM, speed, and oil temperature through the diagnostic port.
A great variety of implemented features and data types exists across various vehicles and equipment.
Can OBD systems work on off-road equipment?
Yes, OBD can be used on any equipment, and it is up to the manufacturer of the equipment to select what diagnostic system is best suited to their equipment.
Some manufacturers offer both types of diagnostic ports, and even a third proprietary data bus. For example, CAT has its own closed system called CDL. This system does not follow CAN protocol standards.
Many manufacturers use OBD or J1939 signaling standards. However, they often use special proprietary connectors, like Kubota or Liebherr. This means you need special connection adapters for diagnostics or monitoring.
Your IoT provider can help you connect to these types of equipment using appropriate adapter cables.