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Can-Bus


dorkweed

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What does this "term" mean?? In small words if possible. I've heard this term a lot here since I bought my new 2016 Silverado.

I understand that it's something to do with info between places....................I think. I do own a computer; but about all I can do is download pictures, surf the web, print stuff and turn it on and off.

 

Thanks.

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CAN means Controller Area Network; it's a special communications bus that allows the various computers in a vehicle (Engine Control Module, Transmission Control Module, Body Control Module, Electronic Brake Control Module, etc.) to communicate and share data with each other. For example, the Passkey anti theft system will send the "Okay to Start" passcode to the ECM when a proper key is used, and the ECM will turn around and send Engine Speed, Coolant temperature, Fuel Level, Battery Voltage, and Oil Pressure readings to the Instrument Panel Cluster (IPC Module), as well as the TCM sends Vehicle Speed and Gear position (both the PRNDL position, as well as actual gear numbers when in the Tapshift mode)

 

 

Sent to the Interwebs by an Apple

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CAN means Controller Area Network; it's a special communications bus that allows the various computers in a vehicle (Engine Control Module, Transmission Control Module, Body Control Module, Electronic Brake Control Module, etc.) to communicate and share data with each other. For example, the Passkey anti theft system will send the "Okay to Start" passcode to the ECM when a proper key is used, and the ECM will turn around and send Engine Speed, Coolant temperature, Fuel Level, Battery Voltage, and Oil Pressure readings to the Instrument Panel Cluster (IPC Module), as well as the TCM sends Vehicle Speed and Gear position (both the PRNDL position, as well as actual gear numbers when in the Tapshift mode)

 

 

Sent to the Interwebs by an Apple

 

 

Thanks...................what does the "bus" part mean then??

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A 'bus' can be considered how the transport of the protocol occurs, be it over twisted pair, 2 wire, 4 wire, ethernet, the various wireless methods, etc. It is the 'highway' the information takes back and forth.

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Think of it this way. Used to, on throttles, your right foot was connected directly to the throttle plate via the pedal and the attached cable. Now days, the computer controls the throttle via wires carrying an electrical signal. Your foot has no direct connection with the throttle plate anymore. The pedal you mash with your right foot merely sends an electric signal to the computer (no more cable from the pedal to the throttle plate), the computer translates that into voltage, and opens (or closes) the throttle accordingly.

 

Same thing happens when you open the door. Used to, when you'd open your door, the pin would pop out of the door light switch, ground the circuit and pass the voltage along to the interior lights. Now days, when you open the door, the computer receives a low voltage signal that the door is opened, and one of many body control modules passes along that info to the corresponding outlets and activates the lights.

 

You should see the bundles of cables from front to rear in my wife's X5. Nothing mechanical anymore, everything is electrically powered/actuated now.

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Think of it this way. Used to, on throttles, your right foot was connected directly to the throttle plate via the pedal and the attached cable. Now days, the computer controls the throttle via wires carrying an electrical signal. Your foot has no direct connection with the throttle plate anymore. The pedal you mash with your right foot merely sends an electric signal to the computer (no more cable from the pedal to the throttle plate), the computer translates that into voltage, and opens (or closes) the throttle accordingly.

 

Same thing happens when you open the door. Used to, when you'd open your door, the pin would pop out of the door light switch, ground the circuit and pass the voltage along to the interior lights. Now days, when you open the door, the computer receives a low voltage signal that the door is opened, and one of many body control modules passes along that info to the corresponding outlets and activates the lights.

 

You should see the bundles of cables from front to rear in my wife's X5. Nothing mechanical anymore, everything is electrically powered/actuated now.

And electronic throttle control has greatly simplified cruise control; instead of having to send the throttle commands to a standalone actuation servo, the commands are sent to the main throttle servo.

 

 

Sent to the Interwebs by a Phone Shaped Apple

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  • 2 weeks later...

can bus uses the actual power wires of any of the devises for commutation -- and will monitor power being used (and more) for each devise and report anything out of range ... so cutting & splicing wires ca mess up the entire system ... just like the electric company can read your meter using the actual high voltage power wires strung down the street ...

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can bus uses the actual power wires of any of the devises for commutation -- and will monitor power being used (and more) for each devise and report anything out of range ... so cutting & splicing wires ca mess up the entire system ... just like the electric company can read your meter using the actual high voltage power wires strung down the street ...

 

that is fancy.

I don't like the antique serial approach however. FIFO, first in first out.. not that we do a whole bunch of things at once..but vehicles sure do.

 

ever plug in you usb camera..and wonder where the heck it is...

oh, the usb mouse flinched while plugging in the camera and stole the signal.

 

I like the volt monitoring, even checks light bulbs for you. My dad's 2016 pete is can bus. It runs through checks, continuity one end to the other.

the better the electric management, the longer the chassis will last, and we feel clean driving.

 

here is a link to serial:

https://en.wikipedia.org/wiki/Serial_communication

 

other than the fancy volts..

you really don't need can bus from obd2 years onward. Alternators are thinking without us knowing. For GM trucks, if you were heck bent on two batteries, the alternator resorts to the old primal full amps ahead..the only non-thinkers, ape mode.

those chassis' get munched.

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  • 3 weeks later...

If you want a good read for a better understanding of OBD in general look up the book

 

Automotive Diagnostic Systems By keith McCord on Amazon.

 

Has a pretty good overview for a better understanding of the OBD Systems.

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