CAN COMMUNICATION SYSTEM Check CAN Bus Line for Short to GND (LHD Models)

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of DLC3.

  • Short to ground in CAN main bus line

  • Short to ground in CAN branch line

  • Power management control ECU

  • ECM

  • Main body ECU (Multiplex network body ECU)

  • Combination meter assembly

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

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

  • Yaw rate and acceleration sensor

  • Power steering ECU assembly

  • Airbag sensor assembly

  • Transmission control ECU assembly

  • Certification ECU (Smart key ECU assembly)

  • Radio receiver assembly*1*2

  • DCM (Telematics transceiver)*3

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

  • CAN No. 3 junction connector

*1: for Navigation Receiver Type

*2: for Radio and Display Type

*3: w/ Manual (SOS) Switch

WIRING DIAGRAM

A004WIME04
A004WY5E05

CAUTION / NOTICE / HINT

Note


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

  • Turn the power switch off before inspecting CAN bus lines 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 TO GND IN CAN BUS LINE (CAN NO. 2 J/C)


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

    2. A004YV5E02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to CAN No. 1 Junction Connector
      *c to CAN No. 3 Junction Connector
      *d to DLC3
      *e to Power Steering ECU Assembly
      *f to Radio Receiver Assembly (for Navigation receiver type or radio and display type)

      Disconnect the H104 connector from the CAN No. 2 junction connector rear side.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      H104-1 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher CAN No. 1 junction connector
      H104-2 (CANL) - H44-4 (CG)
      H104-4 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher CAN No. 3 junction connector
      H104-5 (CANL) - H44-4 (CG)
      H104-7 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher DLC3
      H104-8 (CANL) - H44-4 (CG)
      H104-10 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      H104-11 (CANL) - H44-4 (CG)
      H104-13 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Radio receiver assembly*1*2
      H104-14 (CANL) - H44-4 (CG)

      *1: for Navigation Receiver Type

      *2: for Radio and Display Type

      Result
      Result Proceed to
      OK A
      NG (DLC3 branch line) B
      NG (CAN No. 1 junction connector main line) C
      NG (CAN No. 3 junction connector main line) D
      NG (ECU or sensor wire) E

    B

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

    C

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C) Click here

    D

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C) Click here

    E

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

    A

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 2 J/C)


    1. A004YKEE02
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)
      *b to Steering Angle Sensor (Spiral Cable with Sensor Sub-assembly)
      *c to Certification ECU (Smart Key ECU Assembly)
      *d to Airbag Sensor Assembly
      *e to Yaw Rate and Acceleration Sensor
      *f to DCM (Telematics Transceiver)

      Disconnect the H105 connector from the CAN No. 2 junction connector front side.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      H105-3 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering angle sensor (Spiral cable with sensor sub-assembly)
      H105-2 (CANL) - H44-4 (CG)
      H105-6 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (Smart key ECU assembly)
      H105-5 (CANL) - H44-4 (CG)
      H105-9 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag sensor assembly
      H105-8 (CANL) - H44-4 (CG)
      H105-12 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate and acceleration sensor
      H105-11 (CANL) - H44-4 (CG)
      H105-15 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher DCM (Telematics transceiver)
      H105-14 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (ECU or sensor wire) B

    A

    REPLACE CAN NO. 2 JUNCTION CONNECTOR

    B

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

  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C)


    1. B001MPEE19
      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 H112 connector from the CAN No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      H112-5 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (Multiplex network body ECU)
      H112-11 (CANL) - H44-4 (CG)
      H112-6 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher CAN No. 2 junction connector
      H112-12 (CANL) - H44-4 (CG)
      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 J/C - CAN NO. 2 J/C)

    C

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

    A

  4. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 1 J/C)


    1. A004XU7E20
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

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

      Disconnect the A57 connector from the CAN No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A57-1 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher ECM
      A57-7 (CANL) - H44-4 (CG)
      A57-2 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU (Brake booster with master cylinder assembly)
      A57-8 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (ECU or sensor wire) B

    A

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

    B

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

  5. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C)


    1. A004XU7E21
      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 Assembly

      Disconnect the H113 connector from the CAN No. 3 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      H113-4 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power management control ECU
      H113-10 (CANL) - H44-4 (CG)
      H113-5 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher CAN No. 2 junction connector
      H113-11 (CANL) - H44-4 (CG)
      H113-6 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter assembly
      H113-12 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (ECU or sensor wire) C

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (CAN NO. 2 J/C - CAN NO. 3 J/C)

    C

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

    A

  6. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN NO. 3 J/C)


    1. A004XU7E22
      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 A58 connector from the CAN No. 3 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A58-1 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Transmission control ECU assembly
      A58-7 (CANL) - H44-4 (CG)
      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 GND 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 ground.

      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. A004X9HE02
      Text in Illustration
      *1 DLC3

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H44-6 (CANH) - H44-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      H44-14 (CANL) - H44-4 (CG)

      Tech Tips

      If the resistance changes to 200 Ω 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 WIRE OR CONNECTOR