CAN COMMUNICATION SYSTEM Open in CAN Main Bus Line

DESCRIPTION

There may be an open circuit in one of the CAN bus main wires and/or a DLC3 branch wire when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is 70 Ω or higher.

Symptom Trouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is 70 Ω or higher.

  • DLC3 branch wire or connector

  • CAN bus main wire or connector

  • Certification ECU

  • ECM

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

WIRING DIAGRAM

A019N6LE01
A019ONME01

INSPECTION PROCEDURE

Note


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

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

  • After the engine 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 1minute and do not operate the engine 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 engine 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.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS WIRE (DLC3 BRANCH WIRE)


    1. Turn the engine switch off.

    2. A019KCZE93
      Text in Illustration
      *1 DLC3

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F17-6 (CANH) - F17-14 (CANL) Engine switch off 108 to 132 Ω

      Note

      When the measured value is 133 Ω or higher and a CAN communication system DTC is output, there may be a fault besides disconnection of the DLC3 branch wire. For that reason, troubleshooting should be performed again from How to Proceed with Troubleshooting after repairing the trouble area Click here.


    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3

    OK

  2. CHECK FOR OPEN IN CAN BUS WIRE (ECM)


    1. A019OJ1E52
      Text in Illustration
      *A for 2GR-FE
      *B for 1AR-FE
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance (for 2GR-FE)
      Tester Connection Switch Condition Specified Condition
      A43-10 (CANH) - A43-11 (CANL) Engine switch off 108 to 132 Ω
      Standard Resistance (for 1AR-FE)
      Tester Connection Switch Condition Specified Condition
      A70-13 (CANH) - A70-5 (CANL) Engine switch off 108 to 132 Ω
      Result
      Result Proceed to
      OK (for 2GR-FE) A
      OK (for 1AR-FE) B
      NG C

    B

    REPLACE ECM Click here

    C

    CHECK FOR OPEN IN CAN BUS WIRE (CERTIFICATION ECU) Click here

    A

    REPLACE ECM Click here

  3. CHECK FOR OPEN IN CAN BUS WIRE (CERTIFICATION ECU)


    1. Reconnect the ECM connector.

    2. A019N51E06
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Certification ECU)

      Disconnect the certification ECU connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F58-9 (CANH) - F58-10 (CANL) Engine switch off 108 to 132 Ω

    NG

    CHECK FOR OPEN IN CAN BUS WIRE (CAN NO. 1 J/C) Click here

    OK

    REPLACE CERTIFICATION ECU

  4. CHECK FOR OPEN IN CAN BUS WIRE (CAN NO. 1 J/C)


    1. A019M7SE61
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *2 to ECM

      Disconnect the CAN No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F70-6 (CANH) - F70-17 (CANL) Engine switch off 108 to 132 Ω

    NG

    REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - ECM)

    OK

  5. CHECK FOR OPEN IN CAN BUS WIRE (CAN NO. 1 J/C - CAN NO. 2 J/C)


    1. Reconnect the certification ECU connector.

    2. A019M7SE62
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *2 to CAN No. 2 Junction Connector

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      F70-7 (CANH) - F70-18 (CANL) Engine switch off 108 to 132 Ω

    NG

    CHECK FOR OPEN IN CAN BUS WIRE (CAN NO. 2 J/C) Click here

    OK

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

  6. CHECK FOR OPEN IN CAN BUS WIRE (CAN NO. 2 J/C)


    1. Reconnect the CAN No. 1 junction connector.

    2. A019M7SE63
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *2 to Certification ECU
      *3 to CAN No. 1 Junction Connector

      Disconnect the CAN No. 2 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Connect to
      F71-2 (CANH) - F71-13 (CANL) Engine switch off 108 to 132 Ω Certification ECU
      F71-7 (CANH) - F71-18 (CANL) Engine switch off 108 to 132 Ω CAN No. 1 junction connector
      Result
      Result Proceed to
      OK A
      NG (to Certification ECU main wire) B
      NG (to CAN No. 1 junction connector main wire) C

    B

    REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 2 J/C - CERTIFICATION ECU)

    C

    REPAIR OR REPLACE CAN BUS MAIN WIRE OR CONNECTOR (CAN NO. 1 J/C - CAN NO. 2 J/C)

    A

    REPLACE CAN NO. 2 JUNCTION CONNECTOR