CANbus also called decoder, it usually used to solve boot( it will generate an ACC), steering wheel control, reversing radar display, display of the original car etc.

1. How to connect the lines of the ISO wiring
harness with CANbus on a car stereo
We have mentioned how to connect the lies of universal ISO
wiring harness before. Now, we are going to talk about the ISO
wiring harness with CANbus.
CANbus also called decoder, it usually used to solve boot( it will
generate an ACC), steering wheel control, reversing radar
display, display of the original car etc.
A car with CANBUS will not have a separate ACC line, small light
line, and other lines. But the driving computer of the car
communicates with the car stereo CANBUS through two data
lines (CAN line), and then CANBUS decodes the corresponding
signal to the car stereo. For example, when reversing, CANBUS
will decode a reverse signal (12V voltage) to the REVERSE line of
the car stereo, and the car stereo will automatically switch to
the reverse interface. And also, when the car's instrument light
switch is turned on, CANBUS will decode a button light signal
(12V voltage) to the car stereo's ILLUMI line, and the machine's

2. button light will light up.
A side is to connect with the car stereo, B side is to connect
with the car, C is standard for CANbus. The REVERSE line and
ILLUMI line on the CANbus ISO wiring harness are directly
produced by CANBUS. They will not be labeled, but the line
position of the A end is the same as the universal ISO wiring
harness. So if we want to find these lines, we can compare the
line position of the universal ones.