CAN COMMUNICATION SYSTEM(for LHD) 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.

      C351786E02

    2. Using the CANH and CANL bus wires as a pair, CAN communication is performed using a voltage differential. (A base voltage is applied to the pair of wires 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, bus 5, sub bus 1, local bus and sub bus 15 each have termination circuits with two resistors of 120 Ω.

    5. The CAN communication system is composed of 7 buses.

  2. DEFINITION OF TERMS

    1. CAN main wire

      1. The CAN main wire is a wire harness between the 2 termination circuits on the bus (communication wire). This is the main bus in the CAN communication system.

    2. CAN branch wire

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

    3. Termination circuits

      1. Two resistors of 120 Ω are installed in parallel across the ends of the CAN main bus wires. They are called terminating resistors. These resistors allow the changes of the voltage differential between the CAN bus wires 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 VIA CAN COMMUNICATION SYSTEM

    1. V Bus

      1. Central gateway ECU

      2. DLC3

    2. Bus 2

      1. ECM

      2. Brake booster with master cylinder assembly (skid control ECU)

      3. Air conditioning amplifier assembly

      4. Main body ECU (multiplex network body ECU)

      5. Airbag sensor assembly

      6. Power steering ECU assembly

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

      8. Certification ECU (smart key ECU assembly)

      9. Hybrid vehicle control ECU

      10. Central gateway ECU

      11. Combination meter assembly

    3. Bus 3 (w/ Audio and Visual System [for Radio and Display Type])

      1. Central gateway ECU

      2. Radio and display receiver assembly

      3. Telematics transceiver*

        • *: w/ Telematics Transceiver

    4. Bus 5

      1. Central gateway ECU

      2. Hybrid vehicle control ECU

      3. Parking assist ECU*1

      4. Driving support ECU assembly*2

      5. Clearance warning ECU assembly*3

      6. Forward recognition camera*2

      7. Blind spot monitor sensor LH*4

      8. Millimeter wave radar sensor assembly*2

      9. Television camera assembly*5

        • *1: w/ Panoramic View Monitor System

        • *2: w/ Pre-crash Safety System

        • *3: w/ TOYOTA Parking Assist-sensor System

        • *4: w/ Blind Spot Monitor System

        • *5: w/ Parking Assist Monitor System (for Camera built-in ECU)

    5. Sub Bus 1 (w/ Power Back Door System)

      1. Main body ECU (multiplex network body ECU)

      2. Multiplex network door ECU

      3. Position control ECU and switch assembly*

        • *: w/ Seat Memory

    6. Local Bus (w/ Pre-crash Safety System)

      1. Driving support ECU assembly

      2. Forward recognition camera

      3. Millimeter wave radar sensor assembly

    7. Sub Bus 15

      1. ECM

      2. Hybrid vehicle control ECU

      3. Brake booster with master cylinder assembly (skid control ECU)

  4. CIRCUIT DESCRIPTION

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

    2. The bus 2, bus 3, bus 5, sub bus 1, local bus and sub bus 15 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 branch wires. If there is a malfunction in the DLC3 or the DLC3 branch wires, ECUs on the CAN cannot output DTCs to the GTS.

  6. DIAGNOSTIC TROUBLE CODES FOR CAN COMMUNICATION SYSTEM

    Tip:

    See Diagnosis System

    Click here

  7. DIAGNOSTIC TROUBLE CODES FOR CAN COMMUNICATION SYSTEM

    1. In the CAN communication system, the shape of all connectors connected to the CAN junction connector is the same.

      The connectors connected to the CAN junction connector can be distinguished by the colors of the bus wire and the connecting side of the connector.

      Tip:

      Refer to "Terminals of ECU" for bus wire color or the connecting side of the connector.

      Click here