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Home › Lexus › 2006 › GX 470 › Repair and Diagnosis › External Pages › Different car › Section 31 (Can Communication) › Can Communication System › System Description

System Description

WARNING: This page is about a different car, the 2006 Lexus GS 430 and 2006 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. BRIEF DESCRIPTION 
    1. The CAN (Control 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 lines, the CAN perform 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 communicate with the main bus line.
  2. DEFINITION OF TERMS 
    1. Main bus line
      1. The main bus line is a wire harness between the two terminus circuits on the bus (communication line). This is the main bus in the CAN communication system.
    2. Sub bus line
      1. The sub bus line is a wire harness which diverges from the main bus line to an ECU or sensor.
    3. Terminus circuit
      1. The terminus circuit is a circuit is placed to convert communication current of the CAN communication into bus voltage. It consists and condenser. Two terminus circuits are necessary on a bus.
    4. CAN J/C
      1. The CAN J/C is a junction designed for CAN communication, which stores a terminus circuit.
  3. ECUs OR SENSORS WHICH COMMUNICATE THROUGH CAN COMMUNICATION SYSTEM 
    1. Skid control ECU with actuator (3GR-FSE)
    2. Skid control ECU (3UZ-FE)
    3. Yaw rate sensor
    4. Steering angle sensor
    5. Television camera ECU
    6. Seat belt control ECU
    7. Distance control ECU
    8. Absorber control ECU
    9. ECM
    10. Gateway ECU
    11. Clearance warning ECU
    12. Power steering ECU
    13. Steering control ECU
    14. 4WD ECU
  4. DIAGNOSTIC CODE FOR CAN COMMUNICATION SYSTEM 
    1. DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0122, U0123, U0124, U0126, U0132, U0145, U1101, U0130, U0131, U0145, U0114, U0146, U0105, U0121, U0104
  5. REMARK FOR TROUBLESHOOTING 
    1. Trouble in the CAN bus (communication line) van be checked from the DLC3 (except when there is a wire break other than in the sub bus line of the DLC3).
      NOTE: Do not insert the tester directly into the DLC3 connector. Be sure to use a service wire.
    2. DTCs reading the CAN communication system can be checked using the intelligent tester via the CAN VIM.
    3. The CAN communication system cannot detect trouble in the sub bus line of the DLC3 even though the DLC3 is also connected to the CAN communication system.
  6. HOW TO DISTINGUISH THE CAN J/C CONNECTOR 
    1. In the CAN communication system, the shape of all connectors connected to the CAN J/C is the same. The connectors connected to the CAN J/C can be distinguished by the colors of the bus line and the connecting side of the connector.

      HINT:

      See TERMINALS OF ECU  and HOW TO PROCEED WITH TROUBLESHOOTING  for bus line color or the type of connecting surface.

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