LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2009 >> LS 460 RWD >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Can Communication >> Can Communication System >> System Description

System Description

  1. 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.
  2. DEFINITION OF TERMS 
    1. Main wire
      1. The main wire is a wire harness between the 2 termination 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. Termination circuits
      1. The termination 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 termination circuits are necessary on a bus.
    4. CAN J/C
      1. The CAN J/C is designed so that it can be used with CAN communication which has a termination circuit and CAN communication which does not have a termination circuit.
  3. CIRCUIT DESCRIPTION 
    1. The V bus, steering bus, braking and driving bus, park assist bus, powertrain bus and MS bus each have termination circuits with 120 Ω x 2 of resistance. High speed communication at 500 kbps and 250 kbps is possible.
  4. ECU OR SENSOR WHICH COMMUNICATE VIA CAN COMMUNICATION SYSTEM 
    1. Skid control ECU
    2. Air conditioning amplifier
    3. ECM
    4. Main body ECU
    5. No. 1 meter ECU
    6. Center airbag sensor
    7. Electric power control ECU
    8. AFS ECU
    9. Display and navigation (Multi-display)*1
    10. Integration control and panel assembly*2
    11. Steering angle sensor
    12. Yaw rate sensor
    13. Power steering ECU
    14. Steering control ECU*3
    15. Suspension control ECU*4
    16. Seat belt control ECU*5
    17. Driving support ECU*6
    18. Electric parking brake ECU
    19. Parking assist ECU*7
    20. Clearance warning ECU*8
    21. Front controller
    22. Outer mirror switch
    23. Steering pad ECU
    24. Multiplex tilt and telescopic ECU
    25. Certification ECU
    26. Front multiplex network door ECU LH
    27. Front multiplex network door ECU RH
    28. Rear multiplex network door ECU LH
    29. Rear multiplex network door ECU RH
    30. Front power seat ECU and switch LH
    31. Front power seat ECU and switch RH*9
    32. Rear power seat module switch*10, *11
    33. Combination switch
    34. Power trunk lid control ECU*12
    35. Rear junction block ECU
    36. Tire pressure warning ECU
    37. Bus buffer ECU*13
    38. Front millimeter wave radar sensor*6
    39. TCM

      HINT:

      *1: w/Multi-display

      *2: w/o Multi-display

      *3: w/ Variable Gear Ratio Steering System

      *4: w/ Air Suspension System

      *5: w/ Pre-collision System

      *6: w/ Dynamic Radar Cruise Control System or Pre-collision System

      *7: w/ Advanced Parking Guidance System and Intuitive Parking Assist System

      *8: w/ Intuitive Parking Assist System

      *9: w/ Rear Power Seat Control System

      *10: w/ Rear Power Seat Control System or Seat Heater System

      *11: w/ Rear Power Seat Control System (w/ Ottoman)

      *12: w/ Power Trunk Lid System

      *13: w/ LEXUS Link System

  5. DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM 
    1. DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0122, U0123, U0124, U0126, U0127, U0128, U0129, U0130, U0131, U0132, U0140, U0141, U0142, U0148, U0151, U0155, U0164, U0182, U0199, U0200, U0201, U0202, U0208, U0209, U0210, U0230, U0235, U0243, U0327, U1000, U1002, U1004, U1005, U1100, U1101, U1104, U1105, U1106, U1110, U1111, U1112, U1113, U1114, U1115, U1119, U1121, B2427, B2621, and B2624
  6. 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).
      NOTE: Do not connect the Techstream directly to the DLC3 connector. Be sure to use a service wire.
    2. DTCs regarding the CAN communication system can be checked using the Techstream.
    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.
  7. HOW TO DISTINGUISH 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 " for bus line color or the type of connecting surface.

scientia non olet · About LEMON Manuals