Can Communication System (For Lhd) System Description

Communication System. Camry. Acv40 Gsv40
Can Communication. Camry. Acv40 Gsv40

  1. BRIEF DESCRIPTION

  1. DEFINITION OF TERMS

  1. ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM

  1. DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM

  1. TROUBLESHOOTING REMARKS

  1. HOW TO DISTINGUISH THE CAN J/C CONNECTOR

Can Communication System (For Lhd) -- 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) 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 (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 enable communication on the main bus wire.


DEFINITION OF TERMS

  1. Main bus wire

    1. The main bus wire is a wire harness between the two terminus circuits on the bus (communication line).

  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. Two resistors of 120 Ω resistance 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, a measurement of resistance between the two CAN bus lines should produce a reading of approximately 60 Ω.


ECUS OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM

  1. Skid control ECU with actuator

  2. Air conditioning amplifier

  3. Main body ECU

  4. Combination meter ECU

  5. Yaw rate sensor (with VSC)

  6. Steering angle sensor (with VSC)

  7. Center airbag sensor

  8. ECM


DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM

  1. DTCs for the CAN communication system are as follows: U0101, U0073, U0100, U0123, U0124, U0126, U0129, and B1499.


TROUBLESHOOTING REMARKS

  1. DTCs for the CAN communication system can be checked using the intelligent tester via the CAN VIM. 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 trouble in the DLC3 or the DLC3 branch wires, ECUs on the CAN network cannot output codes to the intelligent tester via the CAN VIM.

  2. Trouble in the CAN buses (communication lines) 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.

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

HOW TO DISTINGUISH THE CAN J/C CONNECTOR

  1. In the CAN communication system, the shape of all connectors connected to the No. 1 CAN J/C is the same. The connectors connected to the No. 1 CAN J/C can be distinguished by the colors of the bus line and the connecting side of the junction connector.

    HINT:
    See "TERMINALS OF ECU" (CAMRY_ACV40 RM000000XVK00VX.html) for bus line color or the type of connecting surface.