Basics : how does the CAN bus work, how are data exchanged, what interferes with communication, what does a good structure look like and which errors should be avoided.
Secondly, you have to deal with the measuring device itself. What can the meter actually measure ? How do I operate the device ? Which work steps do make sense ? Which readings do I expect in a good bus or in a bad one ? The issue of “What can’t I measure with it?” is also important.
Then it’s time to try out what you’ve learned : First on a working bus : does the meter show the expected data ? What happens when I make small changes ? How does the meter interpret this ?
AI – artificial intelligence – is currently on everyone’s lips. But what does AI only do ? It stores what is normal by feeding the system masses of data. Without a comparative value, it is hard to judge whether something is good or bad.
Therefore, after the first attempts to walk with the new measuring device is far from over. The task now is to create a database with reference values. You run the risk of classifying a signal as “good” too quickly just because you never saw it before and have no database as a reference. Therefore, technicians should measure at as many points in different operating modes as possible on their systems, collect as much data as they can, compile and store lists of nodes and documentation in a meaningful way – preferably before a first failure occurs. For example, it makes little sense to measure at a single measuring point in the vehicle even though the structure has four different bus segments. Here, at least one point should be measured at each segment, preferably at the beginning and end.
But even with all this preparation, finding a mistake will still not be trivial. It is now a matter of making meaningful measurements and drawing the right conclusions in comparison with the old measurement data. Is the bus disturbed at all ? Is the bus itself a problem or is the problem somewhere else ? Questions that are easier to answer by comparison than without data.
It always helps to base troubleshooting on a systematic, logical procedure. Unfortunately, there is no magic formula for this (see complexity and diversity of systems). But once you have gone through the above steps, you have the best prerequisites to solve the problem, find the fault and get your machine up and running again. A technician who has taken these steps has accumulated a wealth of experience that cannot be taken away from him. And with every use, the treasure grows.
Final question :
What does our technician know without a measuring device ?