noriceinside

iTrader: (6)

i work at a chrysler/jeep/dodge dealership and am familiar with the older PCI bus, CAN-C, CAN-B, etc. Then when talking fbodies and diagnosing things i wonder if theres any kind of bus anywhere on these cars. PCM? cluster? anything at all?

2002_Z28_Six_Speed

iTrader: (19)

I²C

Just kidding.

koolaid_kid

iTrader: (21)

Yes, they do. That is how the PCM communicates with all the various sensors and such, including through the OBD port under the dash. I am not sure what protocol it uses, though. I am sure you could Google it and find out.

noriceinside

iTrader: (6)

ok whats that? i need to know this joke.

i can see the DLC under the dash being a bus but what do you mean communicating with the various sensors? i know for a fact pcm to sensors arent bus. those are simply reference, ground, and signal wires. im wondering about PCM, BCM, cluster communications.

koolaid_kid

iTrader: (21)

From Wikipedia "A modern automobile may have as many as 50 electronic control units (ECU) for various subsystems. Typically the biggest processor is the engine control unit, which is also referred to as "ECU" (this is a bit out of date, we call ours a PCM, or Powertrain Control Module, some manufacturers call theirs an ECM, or Engine Control Module if they have a separate TCM, or Transmission Control Module) in the context of automobiles; others are used for transmission, airbags, antilock braking, cruise control, audio systems, windows, mirror adjustment, etc. Some of these form independent subsystems, but communications among others are essential. A subsystem may need to control actuators or receive feedback from sensors. The CAN standard was devised to fill this need.
The CAN bus may be used in vehicles to connect engine control unit and transmission, or (on a different bus) to connect the door locks, climate control, seat control, etc. Today the CAN bus is also used as a fieldbus in general automation environments, primarily due to the low cost of some CAN Controllers and processors."
Hope this helps.

koolaid_kid

iTrader: (21)

CAN-B and CAN-C are protocols that ride on the CAN bus. CAN-B has a lower data rate, while CAN-C is newer and can have a higher data rate. Not sure about the PCI bus in a car...

poconojoe

iTrader: (43)

Yes they use a buss to comunicate between the PCM, BCM, ABS, Air Bags, Dash Cluster, Radio (on some vehicles) and since on some vehicles, some of the sensors, go to the BCM instead of the PCM, those sensors are read through the buss. GM calls theirs Class2 serial datalink

Dan Stewart

GM vehicles do use a serial communication protocol between the controllers. But, it is a proprietary UART (universal asynchronous receiver/transmitter) serial communication developed by GM. SAE has labeled it as GM UART. CAN (controller area network) is another form of serial communication and is owned by Bosch. Licensing fees must be paid to Bosch to use CAN.

Needless to say, both are serial communications protocols. Just different flavors.

noriceinside

iTrader: (6)

thanks. i know a lot about CAN bus i just never got into anything with my car so i was curious.