CAN COMMUNICATION SYSTEM(w/o Central Gateway ECU) Check CAN Bus Line for Short to +B (LHD Models)

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when no resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of the DLC3.

Symptom Trouble Area
No resistance exists between terminals 6 (CANH) and 16 (BAT) or 14 (CANL) and 16 (BAT) of the DLC3.

  • Short to +B in CAN main bus line

  • Short to +B in CAN branch line

  • Power management control ECU

  • ECM

  • Main body ECU (Multiplex network body ECU)

  • Combination meter sub-assembly

  • Brake booster with master cylinder assembly (Skid control ECU)

  • Spiral cable with sensor sub-assembly (Steering angle sensor)

  • Yaw rate sensor

  • Power steering ECU assembly

  • Airbag ECU assembly

  • Transmission control ECU assembly

  • Certification ECU (Smart key ECU assembly)

  • Radio and display receiver assembly*

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

  • CAN No. 3 junction connector

*: for Radio and Display Type

WIRING DIAGRAM

B005XJME11
B005ZVDE15

CAUTION / NOTICE / HINT

Note


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

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

  • 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 Click here.

  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the power switch on (IG), turn the cruise control system on using the cruise control switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 50 km/h (31 mph) or more for at least 1.72 seconds.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

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 TO +B IN CAN BUS LINE (CAN NO. 2 JUNCTION CONNECTOR)


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

    2. B005Z5BE02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to CAN No. 3 Junction Connector
      *c to CAN No. 1 Junction Connector
      *d to Certification ECU (Smart Key ECU Assembly)
      *e to Spiral Cable with Sensor Sub-assembly (Steering Angle Sensor)

      Disconnect the L94 wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder left side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L94-2 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher CAN No. 3 junction connector
      L94-1 (CANL) - L61-16 (BAT)
      L94-5 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher CAN No. 1 junction connector
      L94-4 (CANL) - L61-16 (BAT)
      L94-8 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Certification ECU (Smart key ECU assembly)
      L94-7 (CANL) - L61-16 (BAT)
      L94-11 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Spiral cable with sensor sub-assembly (Steering angle sensor)
      L94-10 (CANL) - L61-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 1 junction connector main line) B
      NG (CAN No. 3 junction connector main line) C
      NG (ECU or sensor branch line) D

    B

    CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 JUNCTION CONNECTOR) Click here

    C

    CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 JUNCTION CONNECTOR) Click here

    D

    CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  2. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 2 JUNCTION CONNECTOR)


    1. B005YVWE03
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to Power Steering ECU Assembly
      *c to Yaw Rate Sensor
      *d to Airbag ECU Assembly
      *e to Radio and Display Receiver Assembly*
      *f to DLC3

      Disconnect the L95 wire harness connector from the CAN No. 2 junction connector (instrument panel connector holder right side).

      *: for Radio and Display Type

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L95-2 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Power steering ECU assembly
      L95-3 (CANL) - L61-16 (BAT)
      L95-5 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Yaw rate sensor
      L95-6 (CANL) - L61-16 (BAT)
      L95-8 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Airbag ECU assembly
      L95-9 (CANL) - L61-16 (BAT)
      L95-11 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Radio and display receiver assembly*
      L95-12 (CANL) - L61-16 (BAT)
      L95-14 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher DLC3
      L95-15 (CANL) - L61-16 (BAT)

      *: for Radio and Display Type

      Result
      Result Proceed to
      OK A
      NG (ECU or sensor branch line) B
      NG (DLC3 branch line) C

    A

    REPLACE CAN NO. 2 JUNCTION CONNECTOR

    B

    CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    C

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

  3. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 JUNCTION CONNECTOR)


    1. B005Y98E03
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *b to Main Body ECU (Multiplex Network Body ECU)
      *c to CAN No. 2 Junction Connector

      Disconnect the L132 wire harness connector from the CAN No. 1 junction connector (instrument panel wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L132-5 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Main body ECU (Multiplex network body ECU)
      L132-11 (CANL) - L61-16 (BAT)
      L132-6 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher CAN No. 2 junction connector
      L132-12 (CANL) - L61-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (Main body ECU branch line) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 1 JUNCTION CONNECTOR - CAN NO. 2 JUNCTION CONNECTOR)

    C

    CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  4. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 1 JUNCTION CONNECTOR)


    1. B005Y1VE02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *b to ECM
      *c to Brake Booster with Master Cylinder Assembly (Skid Control ECU)

      Disconnect the A67 wire harness connector from the CAN No. 1 junction connector (engine room main wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A67-1 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher ECM
      A67-7 (CANL) - L61-16 (BAT)
      A67-2 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Brake booster with master cylinder assembly (Skid control ECU)
      A67-8 (CANL) - L61-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (ECU or sensor bus line) B

    A

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

    B

    CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR) Click here

  5. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 JUNCTION CONNECTOR)


    1. B005Z69E02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 3 Junction Connector)
      *b to Power Management Control ECU
      *c to CAN No. 2 Junction Connector
      *d to Combination Meter Sub-assembly

      Disconnect the L133 wire harness connector from the CAN No. 3 junction connector (instrument panel wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L133-4 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Power management control ECU
      L133-10 (CANL) - L61-16 (BAT)
      L133-5 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher CAN No. 2 junction connector
      L133-11 (CANL) - L61-16 (BAT)
      L133-6 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Combination meter sub-assembly
      L133-12 (CANL) - L61-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (ECU or sensor bus line) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 JUNCTION CONNECTOR - CAN NO. 3 JUNCTION CONNECTOR)

    C

    CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR) Click here

    A

  6. CHECK FOR SHORT TO +B IN CAN BUS LINE (CAN NO. 3 JUNCTION CONNECTOR)


    1. B005ZPDE02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

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

      Disconnect the A68 wire harness connector from the CAN No. 3 junction connector (engine room main wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A68-1 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Transmission control ECU assembly
      A68-7 (CANL) - L61-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (Transmission control ECU assembly branch line) B

    A

    REPLACE CAN NO. 3 JUNCTION CONNECTOR

    B

  7. CHECK FOR SHORT TO +B IN CONNECTED COMPONENT (ECU, SENSOR)


    1. Reconnect all wire harness connectors (CAN No. 1 junction connector, CAN No. 2 junction connector and CAN No. 3 junction connector).

    2. Disconnect the ECU or sensor connected to the CAN bus line that is shorted to +B.

      Tech Tips

      If the ECU or sensor has multiple connectors, disconnect the connector that includes the CAN bus lines. To determine the ECU or sensor that is connected to the shorted bus line, refer to the terminals of ECU tables Click here.

    3. B005XIGE03
      Text in Illustration
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L61-6 (CANH) - L61-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      L61-14 (CANL) - L61-16 (BAT)

      Tech Tips

      If the resistance changes to 6 kΩ or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BUS LINE OR CONNECTOR