CAN COMMUNICATION SYSTEM Check CAN Bus Lines for Short Circuit (LHD Models)

DESCRIPTION

There may be a short circuit in the CAN bus main wire and/or CAN branch wire when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is below 54 Ω.

  • Short in CAN bus main wire

  • Short in CAN bus branch wire

  • Power management control ECU

  • ECM

  • Main body ECU

  • Combination meter

  • Skid control ECU (Brake booster with master cylinder)

  • Steering angle sensor

  • Yaw rate sensor

  • Power steering ECU

  • Center airbag sensor assembly

  • Transmission control ECU

  • Certification ECU

  • Navigation ECU (Navigation receiver assembly)

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

WIRING DIAGRAM

A01JCLPE02
A01JB0CE04

INSPECTION PROCEDURE

Note


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

PROCEDURE


  1. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - CAN NO. 2 J/C)


    1. Turn the power switch off.

    2. A01JAQEE27
      Text in Illustration
      *1

      Front view of wire harness connector

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

      Disconnect the CAN No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-7 (CANH) - L94-18 (CANL) Power switch off 108 to 132 Ω

    NG

    CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - CAN NO. 1 J/C) Click here

    OK

  2. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - COMBINATION METER)


    1. A01JAQEE26
      Text in Illustration
      *1

      Front view of wire harness connector

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-1 (CANH) - L94-12 (CANL) Power switch off 108 to 132 Ω

    NG

    CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER) Click here

    OK

  3. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - DLC3)


    1. A01JAQEE29
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *2 to DLC3

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-5 (CANH) - L94-16 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3

    OK

  4. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - SKID CONTROL ECU)


    1. A01JBTQE11
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Skid Control ECU)

      Disconnect the skid control ECU (brake booster with master cylinder) connector.

    2. A01JAQEE30
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Skid Control ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-10 (CANH) - L94-21 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - SKID CONTROL ECU)

    OK

  5. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - NAVIGATION ECU)

    Tech Tips

    For vehicles without the navigation system, go to the next step.


    1. for HDD:


      1. A01J8R5E02
        Text in Illustration
        *1

        Front view of wire harness connector

        (to Navigation ECU)

        Disconnect the navigation ECU connector.

    2. for DVD:


      1. A01J9E3E20
        Text in Illustration
        *2

        Front view of wire harness connector

        (to Navigation ECU)

        Disconnect the navigation ECU connector.

    3. A01JAQEE64
      Text in Illustration
      *3

      Front view of wire harness connector

      (to CAN No. 1Junction Connector)
      *4 to Navigation ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-6(CANH) - L94-17(CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - NAVIGATION ECU)

    OK

  6. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - STEERING ANGLE SENSOR)


    1. A01J99HE38
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Steering Angle Sensor)

      Disconnect the steering angle sensor connector.

    2. A01JAQEE32
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Steering Angle Sensor

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-2 (CANH) - L94-13 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - STEERING ANGLE SENSOR)

    OK

  7. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - POWER STEERING ECU)


    1. A01J8ITE12
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Power Steering ECU)

      Disconnect the power steering ECU connector.

    2. A01JAQEE31
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Power Steering ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-4 (CANH) - L94-15 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - POWER STEERING ECU)

    OK

  8. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - YAW RATE SENSOR)


    1. A01J9GUE15
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Yaw Rate Sensor)

      Disconnect the yaw rate sensor connector.

    2. A01JAQEE33
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Yaw Rate Sensor

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-8 (CANH) - L94-19 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - YAW RATE SENSOR)

    OK

  9. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - CERTIFICATION ECU)


    1. A01J8IFE09
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Certification ECU)

      Disconnect the certification ECU connector.

    2. A01JAQEE34
      Text in Illustration
      *2

      Front view of wire harness connector

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-9 (CANH) - L94-20 (CANL) Power switch off 108 to 132 Ω

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 1 J/C - CERTIFICATION ECU)

    OK

  10. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C - MAIN BODY ECU)


    1. A01JB1RE02
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Main Body ECU)

      Disconnect the main body ECU connector.

    2. A01JAQEE35
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Main Body ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-3 (CANH) - L94-14 (CANL) Power switch off 1 MΩ or higher

    NG

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

    OK

  11. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 1 J/C)


    1. Reconnect the CAN No. 1 junction connector.

    2. A01JBRRE01
      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
      L61-6 (CANH) - L61-14 (CANL) Power switch off 54 to 69 Ω

      Note


      • The resistance must be measured after the main wire connected ECUs (ECM and combination meter), CAN No. 1 junction connector and No. 2 junction connector are reconnected.

      • The resistance must be measured after the CAN No. 1 junction connector branch wire connected ECU and sensor connectors are disconnected.


    NG

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

    OK

  12. CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR)


    1. A01JBRRE01
      Text in Illustration
      *1 DLC3

      Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.

    2. While observing the resistance value shown on the ohmmeter, reconnect each ECU and sensor connector until the resistance becomes abnormal (below 54 Ω).

      Tech Tips

      If the resistance becomes abnormal when an ECU connector is reconnected, there may be a short in the ECU.


    NEXT

    REPLACE CORRESPONDING ECU OR SENSOR

  13. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - CAN NO. 1 J/C)


    1. Reconnect the CAN No. 1 junction connector.

    2. A01JAQEE36
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *2 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
      L95-3 (CANH) - L95-14 (CANL) Power switch off 108 to 132 Ω

    NG

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

    OK

  14. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - ECM)


    1. A01JAQEE43
      *1

      Front view of wire harness connector

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L95-9 (CANH) - L95-20 (CANL) Power switch off 108 to 132 Ω

    NG

    CHECK FOR SHORT IN CAN BUS WIRES (ECM) Click here

    OK

  15. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - POWER MANAGEMENT CONTROL ECU)


    1. A01JBLQE06
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Power Management Control ECU)

      Disconnect the power management control ECU connector.

    2. A01JAQEE37
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *3 to Power Management Control ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L95-8 (CANH) - L95-19 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 2 J/C - POWER MANAGEMENT CONTROL ECU)

    OK

  16. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - TRANSMISSION CONTROL ECU)


    1. A01JB8XE01
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Transmission Control ECU)

      Disconnect the transmission control ECU connector.

    2. A01JAQEE38
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *3 to Transmission Control ECU

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L95-7 (CANH) - L95-18 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 2 J/C - TRANSSMISSION CONTROL ECU)

    OK

  17. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C - CENTER AIRBAG SENSOR ASSEMBLY)


    1. A01JB0AE14
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Center Airbag Sensor Assembly)

      Disconnect the center airbag sensor assembly connector.

    2. A01JAQEE39
      Text in Illustration
      *2

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *3 to Center Airbag Sensor Assembly

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L95-5 (CANH) - L95-16 (CANL) Power switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BUS BRANCH WIRE OR CONNECTOR (CAN NO. 2 J/C - CENTER AIRBAG SENSOR ASSEMBLY)

    OK

  18. CHECK FOR SHORT IN CAN BUS WIRES (CAN NO. 2 J/C)


    1. Reconnect the CAN No. 2 junction connector.

    2. A01JBRRE01
      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
      L61-6 (CANH) - L61-14 (CANL) Power switch off 54 to 69 Ω

      Note


      • The resistance must be measured after the main wire connected ECUs (ECM and combination meter), CAN No. 1 junction connector and No. 2 junction connector are reconnected.

      • The resistance must be measured after the CAN No. 2 junction connector branch wire connected ECU and sensor connectors are disconnected.


    NG

    REPLACE CAN NO. 2 JUNCTION CONNECTOR

    OK

  19. CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR)


    1. A01JBRRE01
      Text in Illustration
      *1 DLC3

      Connect the probes of an ohmmeter to terminals 6 (CANH) and 14 (CANL) of the DLC3.

    2. While observing the resistance value shown on the ohmmeter, reconnect each ECU and sensor connector until the resistance becomes abnormal (below 54 Ω).

      Tech Tips

      If the resistance becomes abnormal when an ECU connector is reconnected, there may be a short in the ECU.


    NEXT

    REPLACE CORRESPONDING ECU OR SENSOR

  20. CHECK FOR SHORT IN CAN BUS WIRES (COMBINATION METER)


    1. A01JCIOE26
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Combination Meter)

      Disconnect the combination meter connector.

    2. A01JAQEE41
      *2

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *3 to Combination Meter

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L94-1 (CANH) - L94-12 (CANL) Power switch off 1 MΩ or higher

    NG

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

    OK

    REPLACE METER CIRCUIT PLATE NO. 3 (COMBINATION METER ECU) Click here

  21. CHECK FOR SHORT IN CAN BUS WIRES (ECM)


    1. A01JCO3E26
      Text in Illustration
      *1

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. A01JAQEE40
      *2

      Front view of wire harness connector

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L95-9 (CANH) - L95-20 (CANL) Power switch off 1 MΩ or higher

    NG

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

    OK

    REPLACE ECM Click here