CAN COMMUNICATION SYSTEM SYSTEM DESCRIPTION

  1. BRIEF DESCRIPTION

    1. The Controller 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.

      C328839E26

    2. Using the CANH and CANL bus lines as a pair, CAN communication is performed using a voltage differential. (A base voltage is applied to the pair of lines and a voltage differential is created when communicating.)

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

    4. The V bus has termination circuits with two resistors of 60 Ω, and the bus 2, bus 3 and sub bus 12 each have termination circuits with two resistors of 120 Ω.

    5. The CAN communication system is composed of 4 buses.

  2. DEFINITION OF TERMS

    1. Main bus

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

    2. Branch

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

    3. Terminating resistors

      1. Two resistors of 120 Ω are installed in parallel across the ends of the CAN main bus lines. They are called terminating resistors. These resistors allow the changes of the voltage differential between the CAN bus lines to be accurately judged. To allow proper function of CAN communication, it is necessary to have both terminating resistors installed. Since the two resistors are installed in parallel, this results in a measurement of approximately 60 Ω.

  3. ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM

    1. V Bus

      1. Network gateway ECU

      2. DLC3

    2. Bus 2

      1. ECM

      2. Brake actuator assembly (skid control ECU)

      3. Main body ECU (instrument panel junction block assembly)

      4. Pre-collision city sensor*1

      5. Certification ECU (smart key ECU assembly)*2

      6. Power management control ECU*2

      7. Power steering ECU assembly

      8. Yaw rate sensor

      9. Spiral with sensor cable sub-assembly (steering angle sensor)

      10. Airbag sensor assembly

      11. Engine stop and start ECU*3

      12. Air conditioning amplifier assembly*4, *5

      13. Network gateway ECU

      14. Combination meter assembly

        • *1: w/ Pre-collision System

        • *2: w/ Entry and Start System

        • *3: w/ Stop and Start System

        • *4: for 1ZR-FAE, 2ZR-FAE (w/ Entry and Start System)

        • *5: w/o Entry and Start System

    3. Bus 3 (for Radio and Display Type)

      1. Network gateway ECU

      2. Radio and display receiver assembly

    4. Sub Bus 12 (for 1WW)

      1. ECM

      2. Power management control ECU

      3. Air conditioning amplifier assembly*

        • *: w/ Entry and Start System

  4. CIRCUIT DESCRIPTION

    1. The V bus has a termination circuit with a resistor of 60 Ω.

    2. The bus 2, bus 3 and sub bus 12 each have termination circuits with two resistors of 120 Ω.

  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 main lines. If there is any trouble in the DLC3 or the DLC3 main lines, ECUs on the CAN cannot output DTCs to the GTS.

  6. DIAGNOSTIC TROUBLE CODES FOR CAN COMMUNICATION SYSTEM

    Tip:

    See Diagnosis System (Click here).