In a recent article, JCOM1939 Monitor Update Adds CAN Bus Diagnostics and Silent Monitoring Mode, we introduced several improvements currently being prepared for the JCOM1939 Monitor software for Windows. The upcoming release adds improved CAN Bus diagnostics, including receive and transmit error counters, CAN controller status information, CAN Bus load, and…
Posts tagged as “J1939 diagnostics”
Developing, testing, or diagnosing SAE J1939 networks requires more than simply connecting a CAN interface to a PC. Engineers often need to monitor network traffic, decode messages, simulate electronic control units (ECUs), request diagnostic data, and verify that embedded software behaves correctly under real-world conditions. The market offers a wide…
It has been a while since we released new functionality for the JCOM1939 Monitor software for Windows, but recent customer feedback inspired several improvements that make the software even more valuable during development, troubleshooting, and diagnostics. The latest update introduces two important features: Display of the CAN Bus network condition,…
If you work with SAE J1939 long enough, there comes a point where generic CAN monitoring software is no longer enough. You need an application that is tailored to your own project, whether that means displaying proprietary parameters, automating diagnostics, logging data, testing ECUs, or integrating J1939 into a larger…
If you spend enough time working with heavy-duty vehicles, agricultural equipment, construction machinery, or industrial engines, you will eventually encounter proprietary J1939 messages. At that point, many engineers ask the same question: Can I reverse engineer a J1939 network? The short answer is yes—but only to a certain extent. Before…
If you’ve worked with SAE J1939 long enough, you’ve probably experienced the frustration of connecting two devices to a CAN bus and seeing… absolutely nothing happen. No engine data. No diagnostic messages. No responses to requests. Just silence. The good news is that most J1939 communication problems are caused by…
Engine speed is one of the most frequently monitored parameters in any SAE J1939 network. Whether you are developing a dashboard, testing an engine ECU, validating telematics software, or learning how J1939 communication works, engine speed is often the first parameter engineers look at. In this post, we will explain…
One question that appears regularly in SAE J1939 discussions is whether multiple Electronic Control Units (ECUs) can transmit the same Parameter Group Number (PGN). At first glance, the answer seems straightforward: if the J1939 standard defines a message, why shouldn’t multiple devices be allowed to transmit it? In reality, the…
If you have recently started working with SAE J1939, chances are your search history looks something like this: How do I monitor J1939 traffic? What hardware do I need for J1939 development? How do I simulate a J1939 ECU? How can I test my software without connecting to a real…
One of the more common questions when analyzing or simulating SAE J1939 traffic is surprisingly simple: “How accurate must a J1939 message frequency be?” If a message is supposed to be transmitted every 100 milliseconds, does that mean exactly 100 milliseconds? Can it be 101 milliseconds? 105 milliseconds? What happens…
