CAN COMMUNICATION SYSTEM DIAGNOSIS SYSTEM


  1. BUS CHECK (COMMUNICATION MALFUNCTION DTC)

    Tech Tips

    Only CAN communication system DTCs for each ECU can be displayed on the intelligent tester.


    1. A016002E01

      Select "Bus Check" from the "System Select" screen on the intelligent tester.

    2. A01617D

      Select "Communication Malfunction DTC" from the "Bus Check" screen, and then select "Enter".

    3. A01614R

      Select the system of the DTC to be checked and select "Details".

    4. A0161MF

      CAN communication system DTC(s) is/are displayed.

  2. BUS CHECK (COMMUNICATION BUS CHECK)

    Tech Tips

    The ECUs and sensors that are properly connected to the CAN communication system can be displayed using the intelligent tester.


    1. A01617D

      Select "Communication Bus Check" from the "Bus Check" screen.

    2. A01622U

      The screen displays the ECUs and sensors that are properly connected to the CAN communication system.

      Tech Tips

      If ECUs or sensors that should be properly connected are not displayed, there is a communication stop in the system. Click here

    3. A015YYB

      "There is no system connected to the communication bus" is displayed if there are no ECUs or sensors connected to the CAN bus.

  3. CHECK FOR INSTALLED SYSTEMS (ECUS AND SENSORS) THAT ADOPT CAN COMMUNICATION


    1. Systems (ECUs, sensors) that adopt CAN communication vary depending on the vehicle's optional equipment. Check which systems (ECUs, sensors) are installed on the vehicle.

      ECU/Sensor Name Check Method
      ECM Installed on all vehicles
      Skid control ECU Installed on all vehicles
      Steering angle sensor Installed on all vehicles
      Yaw rate sensor Installed on all vehicles
      Power steering ECU Installed on all vehicles
      Center airbag sensor Installed on all vehicles
      Gateway ECU Installed on all vehicles
      Distance control ECU Vehicle with dynamic radar cruise control system
      Seat belt control ECU Vehicle with dynamic radar cruise control system
      Television camera ECU Vehicle with LEXUS navigation system

  4. DTC TABLE BY ECU

    Tech Tips

    If CAN communication system DTCs are output, trouble cannot be determined only by the DTCs. Perform troubleshooting according to How to Proceed with Troubleshooting Click here. (If however, U0235 or U1102 is output alone, see the dynamic radar cruise control system.)


    1. ECM/Intelligent tester display "Engine"

      Tech Tips


      • DTC communication uses the CAN communication system.

      • Distance control ECU data is also output.

      DTC No. Detection Item
      U0100*3 Lost Communication with ECM/PCM "A"
      U0101*1 Lost Communication with Transfer Case Control Module
      U0122*3 Lost Communication with Vehicle Dynamics Control Module
      U0123*3 Lost Communication with Yaw Rate Sensor Module
      U0126*3 Lost Communication with Steering Angle Sensor Module
      U0235*2 Lost Communication with Cruise Control Front Distance Range Sensor
      U1101*3 Lost Communication with Distance Control ECU
      U1102*2 Lost Communication with radar Sensor

      • *1: The ECM is malfunctioning if U0101 is output. Replace the ECM.

      • *2: If U0235 or U1102 is output alone, the CAN communication is normal Click here for U0235, Click here for U1102).

      • *3: Dynamic radar cruise control system DTC.

    2. ECM/Intelligent tester display "ECT"

      Tech Tips


      • DTC communication uses the CAN communication system.

        DTC No. Detection Item
        U0100*1 Lost Communication with ECM/PCM "A"

      • *1: The ECM is malfunctioning if U0100 is output. Replace ECM.

    3. SKID CONTROL ECU/Intelligent tester display "ABS/VSC/TRC"

      Tech Tips

      DTC communication uses the CAN communication system.

      DTC No. Detection Item
      U0073 Control Module communication Bus Off
      U0100 Lost Communication with ECM/PCM "A"
      U0123 Lost Communication with Yaw Rate sensor Module
      U0124 Lost Communication with Lateral Acceleration Sensor Module
      U0126 Lost Communication with Steering Angle Sensor Module

    4. POWER STEERING ECU/Intelligent tester display "EPS"

      Tech Tips

      DTC communication uses the CAN communication system.

      DTC No. Detection Item
      U0100 Lost Communication with ECM/PCM "A"
      U0129 Lost Communication with Brake System Control Module

    5. SEAT BELT CONTROL ECU/Intelligent tester display "Pre-crash Seat Belt"

      Tech Tips

      DTC communication uses the SIL line.

      DTC No. Detection Item
      U0100 Lost Communication with ECM/PCM "A"
      U0122 Lost Communication with Vehicle Dynamics Control Module
      U1101 Lost Communication with Distance Control ECU
      U0151 Lost Communication with Airbag ECU

    6. TELEVISION CAMERA ECU/Intelligent tester display "Parking Assist Monitor"

      Tech Tips

      The DTC is displayed on the multi-display assembly (not displayed on the intelligent tester).

      DTC No. Detection Item
      5C-42 Steering angle sensor communication line malfunction

    7. GATEWAY ECU

      Tech Tips

      The gateway ECU is connected to the CAN communication system, but CAN communication DTCs are not output.

    8. CENTER AIRBAG SENSOR

      Tech Tips

      The center airbag sensor is connected to the CAN communication system, but CAN communication DTCs are not output.

  5. DTC COMBINATION TABLE

    DTC Trouble Mode
    Output from Output DTC Skid Control ECU Communication Stop Mode Steering Angle Sensor Communication Stop Mode Yaw Rate Sensor Communication Stop Mode Gateway ECU Communication Stop Mode ECM Communication Stop Mode
    Skid Control ECU U0073 ○*1 X X X X
    U0123

    □*1

    During driving

    		 X

    □

    During driving

    		 X X
    U0124

    □*1

    During driving

    		 X

    □

    During driving

    		 X X
    U0126

    □*1

    During driving

    □

    During driving

    		 X X X
    ECM U0100 X X X X

    □

    Control distance
    U0122

    □

    Control distance

    		 X X X X
    U0123 X X

    □

    Control distance

    		 X X
    U0126 X

    □

    Control distance

    		 X X X
    U1101 X X X X X
    Power Steering ECU U0100 X X X X ○
    U0129 ○ X X X X
    Seat Belt Control ECU U0100 X X X X ○
    U0122 ○ X X X X
    U1101 X X X X X
    U0151 X X X X X
    DTC Trouble Mode
    Output from Output DTC Distance Control ECU Communication Stop Mode Seat Belt Control ECU Communication Stop Mode Power Steering ECU Communication Stop Mode Television Camera ECU Communication Stop Mode Center Airbag Sensor Communication Stop Mode
    Skid Control ECU U0073 X X X X X
    U0100 X X X X X
    U0123 X X X X X
    U0124 X X X X X
    U0126 X X X X X
    ECM U0100

    □*1

    Control distance

    		 X X X X
    U0122

    □*1

    Control distance

    		 X X X X
    U0123

    □*1

    Control distance

    		 X X X X
    U0126

    □*1

    Control distance

    		 X X X X
    U1101

    □*1

    Control distance

    		 X X X X
    Power Steering ECU U0100 X X ○*1 X X
    U0129 X X ○*1 X X
    Seat Belt Control ECU U0100 X ○*1 X X X
    U0122 X ○*1 X X X
    U0151 X ○*1 X X ○
    U1101 ○ ○*1 X X X

    Tech Tips


    • ○: Set

    • X: Not set or may be set according to the malfunction part when one side of the CAN branch lines opens.

    • □: Set under the condition shown in the table

    • *1: Does not output it during communication error


    • Skid Control ECU Communication Stop Mode: Click here


    • Steering Angle Sensor Communication Stop Mode: Click here


    • Yaw Rate Sensor Communication Stop Mode: Click here




    • Distance Control ECU Communication Stop Mode: Click here


    • Seat Belt Control ECU Communication Stop Mode: Click here


    • Power Steering ECU Communication Stop Mode: Click here


    • Television Camera ECU Communication Stop Mode: Click here


    • Center Airbag sensor Communication Stop Mode: Click here