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What are the connection ports associated with a real life Engine Control Module? I mean what does a CAN bus and related port look like once implemented?

I know the theory of CAN and its electrical connections. I want to see what it looks like once integrated in a machine. I don't own a car which has CAN bus.

Add photos please.

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The harness(es) plugged into a modern ECU generally provide:

  • power (battery voltage)
  • data (CAN to rest of vehicle)
  • data (potentially high-bandwidth like MOST, etc.)
  • sensory inputs for that ECU's function (i.e. O2 sensors, etc.)
  • actuator outputs for that ECU's function (i.e. motor outputs, etc.)

CAN is generally implemented by the MCU inside the ECU + a CAN transceiver IC. The most popular MCUs for use in automotive have 1-2 CAN controllers available as a peripheral on the MCU. Sensory inputs are conditioned and fed into the ECU (may be analog, may be digital, could be LIN, etc.). Acutator outputs (say a motor for door locks or similar) are driven by the MCU through some output stage and fed to a connector.

Any other sideband signals required for that ECU's function will also be present on the connectors.

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  • \$\begingroup\$ I know the theory, I just need to see the thing in real life. Thats why I asked for the pictures. I dont own a car that has a CAN bus inside. \$\endgroup\$ – Febin Sunny Dec 30 '16 at 7:00
  • \$\begingroup\$ Plenty of pictures on google. \$\endgroup\$ – Chu Dec 30 '16 at 10:12
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Most connections onto the CANbus will be via some multipole connector with two pins dedicated to CAN as this is then routed around the car.

You, as a car owner, would not generally gain access to a LRU CANbus connection nor would you know the pins or connector without specifics of the LRU's; and why would you when the automotive industry already provides a service port via the On-Board Diagnostics (OBD) port.

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And you can buy bluetooth dongles so your phone can access such data

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  • \$\begingroup\$ Thanks a bunch; but the OBD connector is for Diagnostic purposes right ? My question is about the ECM. Any one of them !! I need to know how the CAN bus is in reality, along with the meand it uses to connect the ECMs...... Is it simply a twisted pair ? How is the bus terminated in real life ? What is port used to connect the ECU to the BUS ? Please help. \$\endgroup\$ – Febin Sunny Dec 30 '16 at 10:44
  • \$\begingroup\$ as I said, this is LRU specific. the main databus connector on the ECU will be different in a Ford, a VW, a ... as such LRU's are designed specifically for that manufacturer. I could show you a generic 38999 connector and it would just as useful. My point is you don't need to know as the OBD connector accesses the CANBUS so if you wanted to snoop that is the place to snoop \$\endgroup\$ – JonRB Dec 30 '16 at 10:53

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