Can Communication System System Description

Communication System. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35
Can Communication. Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35

  1. BRIEF DESCRIPTION

  1. DEFINITION OF TERMS

  1. CIRCUIT DESCRIPTION

  1. ECU OR SENSOR WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM

  1. DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM

  1. NOTES REGARDING TROUBLESHOOTING

Can Communication System -- System Description



BRIEF DESCRIPTION

  1. The CAN (Controller Area Network) is a serial data communication system for real time application. It is a vehicle multiplex communication system which has a high communication speed (500 kbps, 250 kbps) and the ability to detect malfunctions.

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

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

  4. The CAN has 2 resistors of 120 Ω which are necessary to communicate with the main wire.


DEFINITION OF TERMS

  1. Main wire

    1. The main wire is a wire harness between the 2 terminus circuits on the bus (communication line). 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 wire to an ECU or sensor.

  3. Terminus circuit

    1. The terminus circuit is a circuit which converts the communication current of the CAN communication into the bus voltage. It consists of a resistor and condenser. 2 terminus circuits are necessary on a bus.

  4. CAN J/C

    1. The CAN J/C is a junction designed for CAN communication, which contains a terminus circuit.


CIRCUIT DESCRIPTION

  1. In vehicles equipped with the entry and start system, the CAN communication system is composed of a main body ECU and 2 bus circuits (CAN No. 1 bus and CAN No. 2 bus), which are controlled by the main body ECU.

  2. The CAN No. 1 bus and CAN No. 2 bus each have terminus circuits which use 120 Ω of resistance, and are capable of high speed communication (500 kbps for the CAN No. 1 bus, and 250 kbps for the CAN No. 2 bus).


ECU OR SENSOR WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM

  1. Brake actuator (Skid control ECU)*1

  2. ABS and traction actuator (Skid control ECU)*2

  3. Power steering ECU

  4. Steering angle sensor*5

  5. Yaw rate sensor*2

  6. ECM

  7. Center airbag sensor

  8. Air conditioning amplifier

  9. Combination meter ECU

  10. Main body ECU

  11. 4WD control ECU*3

  12. Certification ECU*4

    1. *1: w/ Anti-lock Brake System
    2. *2: w/ Vehicle Stability Control System
    3. *3: for 4WD
    4. *4: w/ Entry and Start System
    5. *5: for 2WD (w/ Vehicle Stability Control System) and 4WD

DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM

  1. DTCs for the CAN communication system are as follows: U0073, U0100, U0105, U0121, U0122, U0123, U0124, U0126, U0129, C1280, C1296, C1297, B1207*, B2326*, and B1499. (*: w/ Entry and Start System)


NOTES REGARDING TROUBLESHOOTING

  1. Trouble 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).

    NOTICE:
    Do not connect the tester directly to the DLC3 connector. Be sure to use a service wire.

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

  3. The CAN communication system cannot detect trouble in the branch line of the DLC3 even though the DLC3 is also connected to the CAN communication system.