CAN COMMUNICATION SYSTEM SYSTEM DESCRIPTION


  1. BRIEF DESCRIPTION


    1. The Control Area Network (CAN) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed and the ability to detect malfunctions.

    2. By pairing the CANH and CANL bus wires, the CAN performs communication based on differential voltage.

    3. Many ECUs or sensors installed on the vehicle operate by sharing information and communicating with each other.

    4. The CAN has two resistors of 120 Ω which are necessary to communicate with the main bus wire.

  2. DEFINITION OF TERMS


    1. Main bus wire


      1. The main bus wire is a wire harness between the two terminating resistors on the bus (communication wire). This is the main bus in the CAN communication system.

    2. Branch wire


      1. The branch wire is a wire harness which diverges from the main bus wire to an ECU or sensor.

    3. Terminating resistors


      1. The termination circuit is a circuit which converts the communication current of CAN communication into the bus voltage. It consists of a resistor and condenser. Two termination circuits are necessary on the bus.

  3. ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM


    1. V1 Bus


      1. ECM

      2. Power management control ECU

      3. Combination meter assembly

      4. Brake booster with master cylinder (Skid control ECU)

      5. Steering angle sensor

      6. Yaw rate and acceleration sensor

      7. Power steering ECU assembly

      8. Plugin charge control ECU assembly

      9. Certification ECU (Smart key ECU assembly)

      10. Main body ECU

      11. Navigation ECU sub-assembly (Navigation receiver assembly)*1

      12. Radio and display receiver assembly*2

    2. V2 Bus


      1. Power management control ECU

      2. Transmission control ECU assembly

      3. Parking assist ECU*3

      4. Driving support ECU*4

      5. Seat belt control ECU*5

      6. Center airbag sensor assembly

      7. Air conditioning amplifier assembly

    3. Power Management Bus


      1. Power management control ECU

      2. ECM

      3. Brake booster with master cylinder (Skid control ECU)

    4. Parking Assist Bus*4*5


      1. Driving support ECU

      2. Millimeter wave radar sensor assembly

        Tech Tips

        *1: for Navigation receiver type

        *2: for Radio and display type

        *3: w/ Intelligent parking assist system

        *4: w/ Dynamic radar cruise control system

        *5: w/ Pre-crash safety system

  4. CIRCUIT DESCRIPTION


    1. The V1 bus, V2 bus, power management bus and parking assist bus each have termination circuits with two resistors of 120 Ω. High speed communication at 500 kbps is possible.

  5. TROUBLESHOOTING REMARKS


    1. DTCs for the CAN communication system can be checked using the GTS. The DLC3 is connected to the CAN communication system, but no DTCs exist regarding problems in the DLC3 or the DLC3 branch wires. If there is any trouble in the DLC3 or the DLC3 branch wires, ECUs on the CAN network cannot output codes to the GTS.

    2. Trouble in the CAN buses (communication wires) can be checked by measuring the resistance between terminals of the DLC3. However, an open circuit in a branch wire other than the DLC3 branch wires cannot be checked from the DLC3.

      Note

      Do not insert the tester probes directly into the DLC3. Be sure to use service wires.

  6. DIAGNOSTIC TROUBLE CODE FOR CAN COMMUNICATION SYSTEM


    1. DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0103, U0104, U0110, U0122, U0123, U0124, U0126, U0129, U0131, U0140, U0142, U0146, U0151, U0155, U0164, U019B, U0235, U0293, U029A, U0327, U0424, U1000, U1002, U1100, U1104, U1105, U1107, U110B, U1133 and U1135.

  7. NOTES REGARDING TROUBLESHOOTING


    1. A malfunction in the CAN bus (communication line) can be checked through the DLC3 (except when there is a wire break other than in the branch wire of the DLC3).

      Note

      Do not insert the tester probes directly into the DLC3. Be sure to use service wires.

    2. DTCs regarding the CAN communication system can be checked using the GTS.

    3. The CAN communication system cannot detect a malfunction in the branch wires for the DLC3 even though the DLC3 is also connected to the CAN communication system.

  8. HOW TO DISTINGUISH CONNECTOR OF CAN JUNCTION CONNECTOR


    1. In the CAN communication system, the shape of connectors connected to the CAN junction connector which has an earth terminal is the same. The connectors connected to the CAN junction connector can be distinguished by the colors of the bus wires and the connecting side of the junction connector.

      Tech Tips

      See Terminals of ECU for bus wire color or the shape of connecting surface Click here.