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How To Proceed With Troubleshooting

NOTE:
  • DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0122, U0123, U0124, U0126, U1101, U0105, U0121.
  • Refer to troubleshooting of each system if DTCs regarding the CAN communication system are not output.
  1. CHECK AND CLEAR DTCS 

    HINT:

    • CAN communication DTCs are output when there is an open or short in any of the communication lines. Any problems with the power source of a corresponding ECU or sensor, or problems in the ECU or the sensor itself also cause these DTCs to be output.
    • If a CAN communication line connector is disconnected with the engine switch on (IG), the ECUs of the corresponding system and related systems record a DTC.
  2. CHECK FOR INSTALLED SYSTEMS (ECUS & SENSORS) THAT ADOPT CAN COMMUNICATION) 
    1. Check if the vehicle is equipped with any of the following: 4WD, dynamic radar cruise control and VDIM systems. (See DIAGNOSIS SYSTEM  )
  3. CHECK CAN BUS LINE 
    1. Check the CAN bus lines (See CAN Bus Line  ).
  4. CHECK WITH INTELLIGENT TESTER 
    1. Using the intelligent tester, display the "BUS CHECK" screen. (See DIAGNOSIS SYSTEM  )
    2. Observe the screen for approximately 1 minute to check the ECUs and sensors displayed on the screen.

    Result 

    RESULT DESCRIPTION TABLE

    Symptom Proceed to
    All ECUs and sensors connected to the CAN communication system are displayed on the screen. A
    Some of the ECUs and sensors connected to the CAN communication system are not displayed on the screen. B
    Some of the ECUs and sensors connected to the CAN communication system are not displayed on the screen. During this check, some ECUs and sensors repeatedly appear and disappear from the screen. C

    See Procedure 

    RESULT DESCRIPTION TABLE

    Result See Procedure
    A Go to  5
    B (See PROBLEM SYMPTOMS TABLE  )
    C (See Open in One Side of CAN Branch Line  )
    NOTE:
    • The systems (ECUs, sensors) that adopt CAN communication vary depending on the vehicle and optional equipment. Check which systems (ECUs, sensors) are installed on the vehicle (See DIAGNOSIS SYSTEM  ).
    • Non-installed ECUs or sensors will not be displayed. Do not mistake them for being in the communication stop mode.
    • The ECUs and sensors that repeatedly appear and disappear from the screen during this check are considered normal. (The response to the intelligent tester and the tester display are affected by signals output from other ECUs which have an open circuit in either of their CAN branch lines.)

    B: COMMUNICATION STOP MODE TABLE 

    C: GO TO  OPEN IN ONE SIDE OF CAN BRANCH LINE  

    A: Go to next step. 

  5. DTC COMBINATION TABLE 
    1. Confirm trouble according to the combination of output DTCs regarding the CAN communication system (See DIAGNOSIS SYSTEM  ).

      HINT:

      Previous CAN communication system DTCs may be the cause if CAN communication system DTCs are output and all ECUs and sensors connected to the CAN communication system are displayed on the intelligent tester's "BUS CHECK" screen via the CAN VIM.

  6. CIRCUIT INSPECTION 

    Go to next step. 

  7. IDENTIFICATION OF PROBLEM 
  8. REPAIR OR REPLACE 
  9. CONFIRMATION TEST 

    END 

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