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System Description

WARNING: This page is about a different car, the 2008 Lexus LS 600hL. However, it is still accessible from the selected car via links, so may be relevant.
  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, HV engine 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. Hybrid vehicle control ECU
    5. Main body ECU
    6. No 1 meter ECU
    7. Center airbag sensor
    8. AFS ECU
    9. Display and navigation (Multi-display)
    10. Steering angle sensor
    11. Yaw rate sensor
    12. Power steering ECU
    13. Steering control ECU
    14. Suspension control ECU
    15. Seat belt control ECU*1
    16. Driving support ECU*2
    17. Electric parking brake ECU
    18. Parking assist ECU*3
    19. Clearance warning ECU*4
    20. Front active stabilizer control ECU*5
    21. Rear active stabilizer control ECU*5
    22. Front controller
    23. Outer mirror switch
    24. Steering pad ECU
    25. Multiplex tilt and telescopic ECU
    26. Certification ECU
    27. Front multiplex network door ECU LH
    28. Front multiplex network door ECU RH
    29. Rear multiplex network door ECU LH
    30. Rear multiplex network door ECU RH
    31. Front power seat ECU and switch LH
    32. Front power seat ECU and switch RH*6
    33. Rear power seat module switch*7, *8
    34. Combination switch
    35. Power trunk lid control ECU*9
    36. Rear junction block ECU
    37. Tire pressure warning ECU
    38. Bus buffer ECU*10
    39. Front millimeter wave radar sensor*2
    40. Object recognition ECU*11
    41. Driver monitor ECU*11

      HINT:

      *1 w/ Pre-collision System

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

      *3. w/ Advanced Parking Guidance System and Intuitive Parking Assist System

      *4 w/ Intuitive Parking Assist System

      *5 w/ Active Stabilizer Suspension System

      *6. w/ Rear Power Seat Control System

      *7. w/ Rear Power Seat Control System or Seat Heater System

      *8. w/ Rear Power Seat Control System (w/ Ottoman)

      *9: w/ Power Trunk Lid System

      *10 w/LEXUS Link System

      *11. w/ Driver Monitor Camera

  5. DIAGNOSTIC CODES FOR CAN COMMUNICATION SYSTEM 
    1. DTCs for the CAN communication system are as follows. U0073, U0100, 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, U0293, U0327, U1000, U1002, U1004, U1005, U1100, U1101, U1104, U1105, U1106, U1108, U1109, 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 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.
  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.

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