CAN COMMUNICATION SYSTEM HOW TO PROCEED WITH TROUBLESHOOTING

DTC Code DTC Name
HOW TO PROCEED WITH TROUBLESHOOTING

CAUTION / NOTICE / HINT


  1. IMPORTANT POINTS CONCERNING TROUBLESHOOTING

    CAUTION:

    Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS system.

    Note


    • Refer to the troubleshooting procedures of each system if DTCs regarding the CAN communication system are not output.

    • Before measuring the resistance, leave the vehicle for at least 1 minute and do not operate the ignition switch, any switches or any doors. If doors need to be opened in order to check connectors, open the doors and leave them open.

    • When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

    Tech Tips


    • Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

    • *: Use the intelligent tester.


    1. DTCs indicating a CAN communication malfunction are also stored due to internal or power source-related problems in ECUs or sensors of systems using CAN communication. Therefore, check whether codes indicating internal or power source-related problems in those systems are output together with the CAN communication DTCs.

    2. It is possible to inspect the circuit of the DLC3 branch line or V1 bus main line for malfunctions by inspecting the terminals of the DLC3 using an electrical tester.

      Note

      It is only possible to inspect branch lines to ECUs (sensors) or the V1 bus from the DLC3.

    3. It is possible to check which ECUs (sensors) are not able to communicate via CAN communication by checking the "Bus Check" function of the intelligent tester (when the DLC3 branch wire and V1 bus main wire are normal).

      Tech Tips


      • When checking "Bus Check", ECUs (sensors) whose branch line is open or that cannot communicate via CAN communication do not respond to the intelligent tester (they are not displayed on the screen).

      • When checking "Bus Check", if a DTC indicating a CAN communication malfunction is output even though all ECUs (sensors) respond (they are displayed on the screen), use the DTC combination table to determine the suspected trouble area and perform symptom simulation.

    4. For past malfunctions of the V1 bus, the ECUs (sensors) which cannot communicate via CAN communication can be determined from the combination of CAN communication DTCs that are output.

    5. The ECM detects malfunctions in the power train bus circuit and stores DTCs depending on the malfunctioning areas. The ECUs (sensors) which cannot communicate via CAN communication can be determined from the combination of CAN communication DTCs that are output.

    6. When an open circuit malfunction is confirmed, before disconnecting the connectors for inspection, check whether the connectors are loose by pushing in the connector case.

    7. When a connector is disconnected, check if the connector terminals or case is damaged, deformed, deteriorated, etc.

PROCEDURE


  1. VEHICLE BROUGHT TO WORKSHOP

    Result
    Result
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  2. INSPECT BATTERY VOLTAGE

    Standard voltage
    11 to 14 V

    If the voltage is below 11 V, recharge or replace the battery before proceeding.

    Result
    Result
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  3. CHECK AND CLEAR DTC*


    1. Using the intelligent tester, perform the all DTCs check.

      Note


      • If codes indicating internal or power source-related malfunctions of ECUs or sensors are output together with codes indicating that those ECUs or sensors cannot communicate via CAN communication, it is likely that the problem is not in the CAN communication line. Therefore, perform troubleshooting for the DTCs related to the malfunctioning parts first.

      • If a connector of a system which includes a CAN communication line is disconnected when the ignition switch is ON or ACC, CAN communication DTCs will be stored by that system and any related systems.

      Result
      Result
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  4. CHECK INSTALLED SYSTEMS (ECU AND SENSOR) THAT USE CAN COMMUNICATION


    1. Based on the vehicle equipment and specifications, confirm the systems that use CAN communication.

      Click here

      Result
      Result
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  5. CHECK FOR OPEN CIRCUIT IN DLC3 BRANCH WIRE AND V1 BUS CIRCUIT MAIN WIRE AND SHORT CIRCUI (CANH - CANL)


    1. Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the main wire and branch wire.

    2. A005GYNC01
      *a Front view of DLC3

      Measure the resistance of the DLC3.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F4-6 (CANH) - F4-14 (CANL) Ignition switch off 54 to 69 Ω
      Result
      Result Proceed to
      OK (54 to 69 Ω) A
      NG (Higher than 70 Ω) (for LHD) B
      NG (Higher than 70 Ω) (for RHD) C
      NG (Below 54 Ω) (for LHD) D
      NG (Below 54 Ω) (for RHD) E

    B

    GO TO "Open in CAN Main Bus Line (LHD Models)" Click here

    C

    GO TO "Open in CAN Main Bus Line (RHD Models)" Click here

    D

    GO TO "Check CAN Bus Lines for Short Circuit (LHD Models)" Click here

    E

    GO TO "Check CAN Bus Lines for Short Circuit (RHD Models)" Click here

    A

  6. CHECK FOR SHORT TO +B IN CAN V1 BUS (CANH, CANL - BAT)


    1. A005IBOC01
      *a Front view of DLC3

      Measure the resistance of the DLC3.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F4-6 (CANH) - F4-16 (BAT) Ignition switch off 6 kΩ or higher
      F4-14 (CANL) - F4-16 (BAT) Ignition switch off 6 kΩ or higher
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    GO TO "Check CAN Bus Line for Short to +B (LHD Models)" Click here

    C

    GO TO "Check CAN Bus Line for Short to +B (RHD Models)" Click here

    A

  7. CHECK FOR SHORT TO GND IN CAN V1 BUS (CANH, CANL - CG)


    1. A005IGSC01
      *a Front view of DLC3

      Measure the resistance of the DLC3.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F4-6 (CANH) - F4-4 (CG) Ignition switch off 200 Ω or higher
      F4-14 (CANL) - F4-4 (CG) Ignition switch off 200 Ω or higher
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    GO TO "Check CAN Bus Line for Short to GND (LHD Models)" Click here

    C

    GO TO "Check CAN Bus Line for Short to GND (RHD Models)" Click here

    A

  8. CHECK ECUS CONNECTED TO CAN BUS*


    1. Connect the cable to the negative (-) battery terminal.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected.

      Click here

    2. Select "Bus Check" from "System Select".

    3. Check the display of the connected ECUs and sensors for a minute.

      Result
      Inspection Result Proceed to
      All ECUs and sensors connected to CAN communication system displayed on screen (CAN bus circuit currently normal) A
      A single ECU or sensor that should be connected to CAN communication is not displayed (ECU or sensor branch wire open or communication stop) B
      ECU or sensor that should be connected to CAN communication is not displayed or display is intermittent during check (ECU or sensor branch wire open on one side) C

      Note

      ECUs and sensors that are not present will not be displayed. Be careful not to mistake them for communication stop malfunctions.

      Tech Tips

      If the display of an ECU is intermittent during the check, one side of an ECU or sensor branch wire is open (the signal of the ECU is treated as noise, which affects the response and display of the intelligent tester).


    B

    GO TO "Problem Symptoms Table" Click here

    C

    GO TO "Open in One Side of CAN Branch Line" Click here

    A

  9. CHECK COMMUNICATION MALFUNCTION DTC (PAST DTC CHECK)*


    1. Select "Bus Check" from "System Select".

    2. Write down all of the DTCs output from each ECU.

      Tech Tips

      If there are communication malfunction DTCs output but the intelligent tester "Bus Check - Communication Bus Check" screen displays all of the ECUs and sensors connected to the CAN system, the

      Result
      Result
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  10. CHECK DTC COMBINATION TABLE (V1 BUS BRANCH WIRE OPEN, PAST COMMUNICATION STOP MALFUNCTION)


    1. Based on the combination of output CAN communication system DTCs, determine which ECUs and sensors have a communication stop malfunction.

      Click here

      Result
      Result
      NEXT

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  11. PERFORM MALFUNCTION SIMULATION TEST (V1 BUS CIRCUIT MAIN WIRE PAST MALFUNCTION)*


    1. Using the intelligent tester, clear all DTCs.

    2. Perform a malfunction simulation test on all harnesses and connectors related to the V1 bus main wire.

    3. Check the DTCs that were output as a result of the malfunction simulation test. Then determine the malfunctioning area.

      Result
      Proceed to
      NEXT

    NEXT

  12. ADJUST, REPAIR AND REPLACE

    Result
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    NEXT

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  13. CLEAR DTC*


    1. Using the intelligent tester, clear all DTCs.

      Result
      Proceed to
      NEXT

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  14. CONFIRMATION TEST

    Result
    Proceed to
    NEXT

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    END