CAN COMMUNICATION SYSTEM(w/ Toyota Safety Sense) HOW TO PROCEED WITH TROUBLESHOOTING

DTC Code DTC Name
HOW TO PROCEED WITH TROUBLESHOOTING

CAUTION / NOTICE / HINT


  1. PRECAUTIONS WHEN TROUBLESHOOTING

    Note


    • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

    • If the CAN communication system is malfunctioning, check the contact pressure of the terminals in connectors, as insufficient terminal contact pressure may be the cause.

      Click here

    • Refer to Diagnosis System for the DTCs for the CAN communication system.

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

    • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

    • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

      Click here


    1. CAN communication DTCs are output for CAN main bus and CAN branch malfunctions as well as for internal malfunctions or power source malfunctions of ECUs or sensors for systems using CAN communication. Therefore, when DTCs for internal malfunctions or power source malfunctions of corresponding systems are output at the same time as CAN communication DTCs, troubleshoot according to the internal malfunction and power source malfunction DTCs.

    2. An open in a branch for ECUs or sensors that are connected to the CAN main bus can be checked by performing a communication bus check using the GTS. (This inspection is possible when all main bus lines are normal.)

    3. If there was a communication error, the probable ECU or sensor for which communication stopped can be determined using the combination of communication DTCs (DTCs that start with U) that are output.

    4. When an open circuit is detected, before disconnecting related connectors for inspection, push in on the connector body to check that the connector is not loose or disconnected.

    5. When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. VEHICLE BROUGHT TO WORKSHOP

    Tech Tips


    • If the ignition switch can be turned to ON (the power source mode can be changed to ON) when the vehicle is brought in for repair, check for DTCs and check the illumination condition of the indicators in the combination meter assembly and the basic operation of the vehicle (such as steering operation) promptly.

    • Do not turn the ignition switch off until the inspection of the vehicle is finished, as some fail-safe functions are canceled when the ignition switch is turned off.

    • If the ignition switch cannot be turned to ON (the power source mode cannot be changed to ON) when the vehicle is brought in, measure the voltage of the battery. If the voltage is below 11 V, recharge or replace the battery before performing troubleshooting.

    • If the ignition switch cannot be turned to ON even though the battery voltage is normal, repair this malfunction before performing troubleshooting.

      Click here

    Result
    Result
    NEXT

    NEXT

  2. CUSTOMER PROBLEM ANALYSIS

    Tech Tips


    • When troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred.

    • Ask the customer if the vehicle is/was equipped with additional devices such as a theft deterrent device or monitor. (If equipped, explain the customer that the additional devices will be removed before performing troubleshooting as the malfunction cannot be checked properly.)


    1. It is useful to confirm the symptoms and the conditions in which the vehicle was operating at the time when a malfunction occurred. This helps to narrow down the malfunctioning part.

      Tech Tips


      • What was affected (system, part or meter warning indicators)

      • What happened (details of the malfunction)

      • When (occurrence date and time, frequency and if it recurs or not)

      • Under what kind of situation did the problem occur (driving and operating condition at the occurrence and weather)

      • Road type or condition (city, suburb, paved road, unpaved road, highway, etc.)

      • Return conditions (what made the vehicle return to normal. Example: ignition switch was turned off)

        Points to be confirmed
        Symptom

        • Electric power steering


          • Normal

          • A little heavier than usual

          • There was no assist

        • Air conditioning


          • Whether the air conditioning system operated

          • Whether the blower fan operated

        • Wireless door lock function and entry function


          • Whether the lock/unlock function operated

          • Whether the illumination was turned on when the key was brought into a smart detection area

        • Operation of other systems of concern
        Meter warning lights

        • Illumination of warning lights and the order in which they illuminated


          • Check engine (MIL)

          • ABS

          • SLIP

          • Brake

          • EPS

          • SRS

          • Others

        • Meter display


          • Speedometer
      Result
      Result
      NEXT

    NEXT

  3. CHECK GTS OPERATION

    Tech Tips

    Read the GTS operators manual before use.

    Click here


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Check that the GTS and ECUs can communicate with the ignition switch ON.

      Tech Tips


      • If communication is impossible, the GTS screen will indicate an error.

      • If communication between the GTS and ECUs is impossible, either the GTS or vehicle has a malfunction.

      • When communication between the GTS and the vehicle is impossible, but communication is possible when the GTS is connected to another vehicle, the vehicle has the malfunction. Inspect the ECU power source circuits (in this case perform steps 22 to 23 first). In addition, check that the BAT terminal of the DLC3 receives battery voltage (11 V or more).

      • If communication between the GTS and ECUs is still impossible even when the GTS is connected to another vehicle, the GTS has the malfunction. Perform the self tests described in the GTS operators manual. (The GTS may be malfunctioning or its battery may be discharged.)

      Result
      Result Proceed to
      OK (Communication between the GTS and the vehicle is possible.) A
      OK (Communication between the GTS and the vehicle is impossible but communication is possible when connected to another vehicle.) B
      NG (Communication is not possible between the GTS and the vehicle, nor between the GTS and another vehicle.) C

    B

    CHECK V BUS MAIN LINE Click here

    C

    Refer to GTS operator's manual

    A

  4. CHECK DTC (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Central Gateway / Trouble Codes.

      OK
      DTC B1003 is not output.
      Result
      Proceed to
      OK
      NG

    NG

    GO TO STEP 6 Click here

    OK

  5. CHECK DTC


    1. Using the GTS, perform All Codes to read current and history DTCs and record them.

      Note


      • 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, the sensor itself also cause these DTCs to be output.

      • If a CAN communication line connector is disconnected with the ignition switch ON, the ECUs of the corresponding system and related systems store a DTC.

      Tech Tips


      • If an open in a CAN main bus line, a short between the CAN bus lines (CANH and CANL) or a +B or ground short in a CAN bus occurs, DTCs of almost all ECUs and sensors on the CAN bus may be output (or a message indicating a communication error may be displayed on the GTS screen). In this case, check the resistance of the CAN bus (steps 8 to 13) first.

      • If an open occurs in just one of the lines of a CAN branch, DTCs which are not related to malfunctioning parts may be output (DTCs may be displayed randomly), or a message indicating a communication error may be displayed on the GTS.

    2. Read the freeze frame data using the GTS and record it.

      Result
      Result
      NEXT

    NEXT

  6. REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)


    1. Replace the central gateway ECU (network gateway ECU)

      Click here

      Tech Tips

      DTC B1003 is stored when a malfunction is detected in the non-volatile storage of the central gateway ECU (network gateway ECU). As DTC B1003 is not related to a communication malfunction, continue with troubleshooting to find the cause of the communication malfunction after replacing the central gateway ECU (network gateway ECU).

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK DTC


    1. Using the GTS, perform Health Check to read current and history DTCs and record them.

      Note


      • 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 sensor itself also cause these DTCs to be output.

      • If a CAN communication line connector is disconnected with the Ignition switch ON, the ECUs of the corresponding system and related systems store a DTC.

      Tech Tips


      • If an open in a CAN main bus line, a short between the CAN bus lines (CANH and CANL) or a short to ground or +B in a CAN bus occurs, DTCs of almost all ECUs and sensors on the CAN bus may be output (or a message indicating a communication error may be displayed on the GTS screen). In this case, check the resistance of the CAN bus (steps 10 to 15) first.

      • If an open occurs in just one of the lines of a CAN branch, DTCs which are not related to malfunctioning parts may be output (DTCs may be displayed randomly), or a message indicating a communication error may be displayed on the GTS.

    2. Read the freeze frame data using the GTS and record it.

      Result
      Proceed to
      NEXT

    NEXT

  8. PERFORM COMMUNICATION MALFUNCTION CHECK (CONNECTION STATUS CHECK USING GTS)


    1. Select "Communication Malfunction Check" from the screen on the GTS.

    2. Record all the DTCs stored for ECUs and sensors.

      Result
      Result
      NEXT

    NEXT

  9. PERFORM CAN BUS CHECK (CONNECTION STATUS CHECK USING GTS)


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

      Click here

    2. Select "CAN Bus Check" from the screen on the GTS.

    3. Observe the screen for approximately 2 minutes to check the ECUs and sensors displayed on the screen.

      Result
      Result
      NEXT

    NEXT

  10. CHECK CENTRALGATEWAY ECU (NETWORK GATEWAY ECU) BRANCH LINE AND BUS 2 MAIN LINE (CANH - CANL)

    Note

    Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

    Tech Tips

    Operating the ignition 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.


    1. A0049D6C01
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-18 (CA4H) - F135-17 (CA4L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK A
      NG (70 Ω or higher) B
      NG (Below 54 Ω) C

    B

    GO TO OPEN IN BUS 2 MAIN BUS LINE Click here

    C

    GO TO CHECK BUS 2 LINES FOR SHORT CIRCUIT Click here

    A

  11. CHECK FOR SHORT TO GND IN BUS 2 (CANH, CANL - CG)


    1. A0048S5C01
      *1 DLC3
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-18 (CA4H) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F135-17 (CA4L) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    NG

    GO TO CHECK BUS 2 LINE FOR SHORT TO GND Click here

    OK

  12. CHECK FOR SHORT TO +B IN BUS 2 (CANH, CANL - BAT)


    1. A0048S5C02
      *1 DLC3
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-18 (CA4H) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      F135-17 (CA4L) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    GO TO CHECK BUS 2 LINE FOR SHORT TO +B Click here

    OK

  13. CHECK BUS 3 MAIN LINE (CANH - CANL)


    1. A0049D6C02
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-6 (CA3H) - F135-21 (CA3L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result Proceed to
      OK A
      NG (70 Ω or higher) B
      NG (Below 54 Ω) C

    B

    GO TO OPEN IN BUS 3 MAIN BUS LINE Click here

    C

    GO TO CHECK BUS 3 LINES FOR SHORT CIRCUIT Click here

    A

  14. CHECK FOR SHORT TO GND IN BUS 3 (CANH, CANL - CG)


    1. A0048S5C04
      *1 DLC3
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-6 (CA3H) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F135-21 (CA3L) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    NG

    GO TO CHECK BUS 3 LINE FOR SHORT TO GND Click here

    OK

  15. CHECK FOR SHORT TO +B IN BUS 3 (CANH, CANL - BAT)


    1. A0048S5C05
      *1 DLC3
      *a Component with harness connected (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F135-6 (CA3H) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      F135-21 (CA3L) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    GO TO CHECK BUS 3 LINE FOR SHORT TO +B Click here

    OK

  16. CHECK RESULT OF CAN BUS CHECK (CONNECTION STATUS CHECK USING GTS)


    1. Inspect or repair the probable malfunctioning part based on the check result of step 9 (the step in which CAN bus check was performed).

      Result of CAN Bus Check (Connection Status Check Using GTS)
      Result Proceed to

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

      (CAN bus circuit is currently normal.)

      		 A

      One of the ECUs and sensors connected to the bus 2 or bus 3, is displayed as communication stop on the screen.

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

      		 B

      In addition to ECUs and sensors which are connected to the bus 2 but are displayed as communication stop 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 lines.)

      		 C

      In addition to ECUs and sensors which are connected to the bus 3 but are displayed as communication stop 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 lines.)

      		 D

      Note


      • Non-installed ECUs or sensors will not be displayed. Do not mistake them for being in communication stop mode.

      • It may be possible to select buses that do not have ECUs or sensors from the bus selection pull-down menu on the GTS. This is not a malfunction. (This occurs when optional devices are not on a sub bus that is monitored by a gateway function equipped ECU.)

      Tech Tips


      • Regarding CAN Bus Check, refer to How to Interpret CAN Bus Check Screen.

        Click here

      • If the detection status of ECUs changes during the inspection, one of the branch lines of a connected ECU or sensor may be open. (Signals from the ECU or sensor that has an open in one of its branch lines create electrical noise, affecting response to the GTS and whether or not the ECUs and sensors are displayed.)

      • Regarding the communication stop mode for ECUs connected to sub bus 1, refer to the inspection procedure for the DTCs that indicate a communication stop.


    B

    GO TO COMMUNICATION STOP MODE TABLE Click here

    C

    GO TO OPEN IN ONE SIDE OF BUS 2 BRANCH LINE Click here

    D

    GO TO OPEN IN ONE SIDE OF BUS 3 BRANCH LINE Click here

    A

  17. CHECK RESULT OF CHECK COMMUNICATION MALFUNCTION DTCs (SELECT THE MALFUNCTIONING BUS)


    1. Inspect or repair the probable malfunctioning part based on the check result of step 7 (the step in which checking for communication malfunction DTCs was performed).

      Tech Tips


      • When checking for communication DTCs, refer to How to Interpret Communication DTCs (DTCs that start with U).

        Click here

      • If communication DTCs are stored, and all ECUs and sensors connected to the CAN communication system are displayed on the Communication Bus Check (CAN bus check) screen of the GTS, a past malfunction that is currently not occurring is suspected.

      • When a CAN branch of the CAN communication system is malfunctioning, because the ECUs and sensors related to it detect the malfunction, the problem area can be determined using the combination of DTCs that are output.

      Result
      Result
      NEXT

    NEXT

  18. DTC COMBINATION TABLE (CANH - CANL)


    1. Confirm the problem according to the combination of output DTCs regarding the CAN communication system.

      Click here

      Result
      Result Proceed to
      Combination of DTCs is not in DTC Combination Table A
      Combination of DTCs is in DTC Combination Table B

      Tech Tips

      CAN communication system history DTCs may indicate the problem if CAN communication system DTCs are output and all ECUs and sensors connected to the CAN communication system are displayed on "Communication Bus Check" of the GTS.


    B

    GO TO COMMUNICATION STOP MODE TABLE Click here

    A

  19. IDENTIFICATION OF PROBLEM (PAST MALFUNCTION IN MAIN BUS)


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

    2. Clear the DTCs using the GTS.

    3. Perform the tests in Symptom Simulation to check the wire harnesses and connectors including those for main bus lines.

      Click here

    4. Based on the results of the check, inspect the parts that output DTCs to determine the malfunctioning part.

      Tech Tips

      If DTCs are output, do not turn the ignition switch off.

      Result
      Result
      NEXT

    NEXT

  20. REPAIR OR REPLACEMENT

    Result
    Result
    NEXT

    NEXT

  21. CONFIRMATION TEST

    Result
    Result
    NEXT

    NEXT

    END

  22. CHECK V BUS MAIN LINE

    Note

    Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

    Tech Tips

    Operating the ignition 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.


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

    2. A0047M6C01
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F4-6 (CANH) - F4-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 66 Ω
      F4-6 (CANH) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F4-14 (CANL) - F4-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F4-6 (CANH) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      F4-14 (CANL) - F4-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CENTRAL GATEWAY ECU - DLC3)

    OK

  23. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. A0047MBC05
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F135-10 (GND) - Body ground Cable disconnected from negative (-) battery terminal Below 1 Ω

    2. Reconnect the cable to the negative (-) battery terminal.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      F135-1 (BATT) - Body ground Always 11 to 14 V
      F135-2 (ACC) - Body ground Ignition switch ACC 11 to 14 V
      F135-11 (IG1) - Body ground Ignition switch ON 11 to 14 V
      F135-12 (IG2) - Body ground Ignition switch ON 11 to 14 V
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)