the joys of being a mechanic

[Steel Armadillo]

Oh, so if you remove one piece, the rest on that loop can't communicate?

EDIT: And is there some other class line? Like a class 1 or class 3?

[IAGXP]

Oh, so if you remove one piece, the rest on that loop can't communicate?

Kind of, some modules will still talk but it depends on what goes down

[Poil336]

Oh, so if you remove one piece, the rest on that loop can't communicate?

EDIT: And is there some other class line? Like a class 1 or class 3?

not exactly... bill will correct me if i'm wrong, but Class2 is one type of data communication. there are others, but typically there isn't more than one found on each car. some use Class2, some use GM LAN... there are others but i forget at the moment. the serial data lines carry voltage references, or signal voltages, for the pcm to use. take a throttle position sensor and the accelerator position pedal sensor. the APP sensor is a potentiometer that varies the voltage input to the pcm. the pcm sends voltage to the TP sensor and idle air control sensor if need be, and those sensors send back a signal voltage, somewhere between 0-5 volts. in this way, the pcm figures out where the throttle plate is and compares it to the APP sensor input to make sure everything's working like it should. it really depends on the car and the system as to removing components, but think of it this way. ALL of the modules (sometimes 20+) communicate with each other. the car might work, but the dash will be lit up like a christmas tree, screaming "hey, one of my buddies just got shot, and i think he's dead". they won't be very happy