Hi Sam,
Check the ground first. Hopefully, it will be something simple. As far as scanning, it does require a scanner that can read can-bus codes. Here is a link that shows in general how it's done. Additionally, there is a video showing it being done.
https://www.2carpros.com/articles/can-scan-controller-area-network-easy
https://youtu.be/InIlnsjOVFA
As far as the can-bus, the newer the vehicles get, the more involved they are. There are more and more modules/computers on cars. If the manufacturer had to run separate wires to each, the car would weigh about 1000 pounds more, hurt MPG, and be much more expensive.
It is confusing, but really interesting how it works. The powertrain control module makes determinations for the car. If two signals come over the same wire at the same time, the PCM determines which is more important. LOL Things just keep getting more and more involved.
Just to let you see it, I attached the schematic below for the computer data lines. Notice there are both high speed and low speed. Notice that all are basically the same colors via high speed. The low speed are all the same colors. That's because that is the single wire running from module to module. Ugh!!! LOL Also, the low speed will always be a single wire circuit that runs basically from a 0v to 5v signal to communicate between circuits that don't require an instant response. A high speed will usually be two wires (often twisted together).
The term bus simply means this. Picture a school bus. Many students ride on the bus to their destination. The concept with the can-bus is a single circuit (similar to one school bus) carries multiple module/computer transmissions to their destinations.
Sorry, since you said you never heard of one, I thought I would try my best to explain it.
If you plan to purchase a scan tool in the future, confirm the one you get can read the can. Sounds funny. LOL You can find them cheap on Amazon. Chances are as time passes; you will get newer vehicles that certainly will require this.
Okay, I will now shut up. I hope this helps explain things a little better.
Take care and let me know what I can do to help.
Joe
See pics below.
Images (Click to make bigger)
Sunday, December 26th, 2021 AT 11:18 PM