CAN COMMUNICATION SYSTEM HOW TO PROCEED WITH TROUBLESHOOTING

Note


  • DTCs for the CAN communication system are as follows: U0073, U0100, U0101, U0103, U0104, U0110, U0122, U0123, U0124, U0126, U0129, U0131, U0140, U0142, U0146, U0151, U0155, U0164, U019B, U0235, U0293, U029A, U0327, U0424, U1000, U1002, U1100, U1104, U1105, U1107, U110B, U1133 and U1135.

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

Tech Tips

*: Use the GTS.


  1. VEHICLE BROUGHT TO WORKSHOP


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  2. CUSTOMER PROBLEM ANALYSIS


    1. Interview the customer and confirm the problem.


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  3. CHECK AUXILIARY BATTERY

    Standard Voltage
    11 to 14 V

    Tech Tips

    If the voltage is below 11 V, recharge or replace the auxiliary battery before proceeding to the next step.


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  4. CHECK AND CLEAR DTCS*

    Tech Tips


    • CAN communication DTCs are stored when there is an open or short in any of the communication wires. 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 stored.

    • If a CAN communication wire connector is disconnected with the power switch on (IG), the ECUs of the corresponding system and related systems store a DTC.


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  5. CHECK FOR DLC3 BRANCH WIRE AND V1 BUS MAIN WIRE (CANH - CANL)

    Note


    • Turn the power switch off before measuring the resistances between CAN main bus wires and between CAN main bus branch wires.

    • Turn the power switch off before inspecting CAN bus wires for a ground short.

    • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

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

    Tech Tips


    • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

    • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.


    1. A0041YHE82

      Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L55-6 (CANH) - L55-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Text in Illustration
      *1 DLC3
      Result
      Result Proceed to
      OK A
      NG (70 Ω or higher) for LHD B
      NG (70 Ω or higher) 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 WIRE (LHD Models) Click here

      C

      GO TO OPEN IN CAN MAIN BUS WIRE (RHD Models) Click here

      D

      GO TO SHORT IN CAN BUS LINES (LHD Models) Click here

      E

      GO TO SHORT IN CAN BUS LINES (RHD Models) Click here

      A

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


    1. A0041YHE83
      Text in Illustration
      *1 DLC3

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L55-6 (CANH) - L55-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      L55-14 (CANL) - L55-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      Result
      Result Proceed to
      OK A
      NG (LHD) B
      NG (RHD) C

      B

      GO TO SHORT TO GND IN CAN BUS WIRE (LHD Models) Click here

      C

      GO TO SHORT TO GND IN CAN BUS WIRE (RHD Models) Click here

      A

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


    1. A0041YHE84
      Text in Illustration
      *1 DLC3

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      L55-6 (CANH) - L55-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      L55-14 (CANL) - L55-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      Result
      Result Proceed to
      OK A
      NG (LHD) B
      NG (RHD) C

      B

      GO TO SHORT TO +B IN CAN BUS WIRE (LHD Models) Click here

      C

      GO TO SHORT TO +B IN CAN BUS WIRE (RHD Models) Click here

      A

  8. 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.


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  9. CHECK ECUS CONNECTED TO CAN BUS*


    1. Select "CAN Bus Check" from the screen on the GTS Click here.

    2. Observe the screen for approximately 1 minute to check the ECUs and sensors displayed on the screen.

      Result
      Result Proceed to

      All ECUs and sensors connected to the CAN communication system are displayed on the screen.

      (CAN bus circuit is currently normal.)

      		 A

      • All ECUs except the power management control ECU connected to the V2 bus are not displayed on the screen.

      • The power management control ECU (power management1) outputs DTC U1002.

      (Open or short in V2 bus main wires.)

      		 B

      When the V1 bus is selected using the drop down list, all the ECUs and sensors connected to the V1 bus are displayed on the screen, but when power management bus is selected, no connected ECUs or sensors are displayed.

      (Open or short in power management bus main wires.)

      		 C

      All ECUs connected to V2 are not displayed on the screen.

      (Open in power management control ECU branch lines or power management control ECU malfunction.)

      		 D

      No ECUs or sensors connected to the ECM or power management bus are displayed on the screen.

      (Open in ECM main wires or ECM malfunction.)

      		 E

      One of the ECUs and sensors connected to the V1 Bus is not displayed on the screen.

      (Open in ECU or sensor branch wires, or communication is interrupted.)

      		 F

      • One of the ECUs and sensors connected to V2 bus is not displayed on the screen.*

        (Open in ECU or sensor branch wires, or communication is interrupted.)

      • One of the ECUs and sensors connected to power management bus is not displayed on the screen.

        (Open in ECU or sensor branch wires, or communication is interrupted.)

      		 G

      In addition to ECUs and sensors which are connected to the CAN communication system but are not displayed on the screen, there are ECUs or sensors for which the detection status changes (changes between detected and not detected) during the inspection.

      (Open in one side of ECU or sensor branch wires.)

      		 H

      Note


      • *: In this case, as the power management control ECU (PM1 Gateway) outputs communication DTCs (DTCs that start with U), the problem area can be determined from those DTCs.

      • The systems (ECUs and sensors) that adopt CAN communication vary depending on the vehicle and optional equipment. Check which systems (ECUs and sensors) are installed on the vehicle Click here.

      • Non-installed ECUs or sensors will not be displayed. Do not mistake them for being in 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 GTS and its display are affected by signals output from other ECUs which have an open circuit in either of their CAN main bus branch wires.)

      Tech Tips

      The ECUs connected to the V2 bus is displayed on the screen by the power management control ECU.


      B

      GO TO U1002 (POWER MANAGEMENT1) Click here

      C

      GO TO U0100, U0129, U0293 Click here

      D

      GO TO POWER MANAGEMENT CONTROL ECU COMMUNICATION STOP MODE Click here

      E

      GO TO ECM COMMUNICATION STOP MODE Click here

      F

      GO TO COMMUNICATION STOP MODE TABLE Click here

      G

      GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

      H

      GO TO OPEN IN ONE SIDE OF CAN MAIN BUS BRANCH WIRE Click here

      A

  10. RECHECK DTC*

    Tech Tips


    • Sometimes CAN communication system DTCs are output, but all ECUs and sensors connected to the CAN communication system are displayed on the GTS. In this case, previous or history DTCs may indicate the cause of the problem.

    • ECUs related to a problem in the CAN bus will store DTCs to indicate communication malfunctions. Communication stop mode in the CAN bus can be determined by comparing the combination of DTCs that have been set. Refer to DTC Combination Table for the CAN bus.

    • The power management control ECU will store communication error DTCs when the ECUs connected to the V2 bus and cannot communicate, or if a network malfunction occurs.

    Result
    Result Proceed to

    • The sub bus monitor ECU has not output communication DTCs but ECUs connected to the V1 bus have stored communication DTCs.

      (A malfunction occurred in the V1 bus.)


    • ECUs connected to power management bus have not output communication DTCs but ECUs connected to the V1 bus have stored communication DTCs.

      (A malfunction occurred in the V1 bus.)


      • The ECM (Engine and ECT) has not output DTC U0293 (Lost Communication with HV ECU).

      • The power management control ECU (Hybrid Control) has not output DTC U0100 (Lost Communication with ECM/PCM "A") or DTC U0129 (Lost Communication with Brake System Control Module).

      • The brake booster with master cylinder (skid control ECU) (ABS/VSC/TRC) has not output DTC U0293 (Lost Communication with HV ECU).

    		 A

    The power management control ECU (Power Management1) outputs DTC 1002.

    (A malfunction occurred in the V2 bus.)

    		 B

    ECUs connected to power management bus store communication error DTCs.

    (A malfunction occurred in the power management bus.)


    • The ECM (Engine and ECT) outputs only DTC U0293 (Lost Communication with HV ECU).

    • The power management control ECU (Hybrid Control) outputs only DTC U0100 (Lost Communication with ECM/PCM "A") and DTC U0129 (Lost Communication with Brake System Control Module).

    • The brake booster with master cylinder (skid control ECU) (ABS/VSC/TRC) outputs only DTC U0293 (Lost Communication with HV ECU).

    		 C

    The power management control ECU (PM1 Gateway) outputs DTCs other than DTC 1002.

    (A malfunction occurred in an ECU branch wire connected to V2 bus.)

    		 D

    The driving support ECU (Pre-Crash 2) outputs DTC 1002.

    (A malfunction occurred in the driving support bus.)

    		 E

    The power management control ECU outputs only DTC U0129 (Lost Communication with Brake System Control Module).

    (A malfunction occurred in an ECU branch line connected to power management bus.)

    		 F

    B

    GO TO U1002 (POWER MANAGEMENT1) Click here

    C

    GO TO U0100, U0129, U0293 Click here

    D

    GO TO DIAGNOSTIC TROUBLE CODE CHART Click here

    E

    GO TO U1002 (PARKING ASSIST BUS) Click here

    F

    GO TO U0129 Click here

    A

  11. DTC COMBINATION TABLE


    1. Confirm the malfunction according to the combination of output DTCs regarding the CAN communication system Click here.

      Tech Tips

      History 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 "CAN Bus Check" of the GTS.


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  12. CIRCUIT INSPECTION


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  13. IDENTIFICATION OF PROBLEM


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  14. REPAIR OR REPLACEMENT


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  15. CONFIRMATION TEST*


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    END