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

  • Multi-media module receiver assembly*1

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

  • CAN No. 3 junction connector

*1: w/ Navigation system

WIRING DIAGRAM

A003XKSE02
A003V9LE03

INSPECTION PROCEDURE

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. Turn the power switch off.

    2. A003X1AE09
      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 Multi-media Module Receiver Assembly

      Disconnect the wire harness 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 Switch Condition Specified Condition Connected to
      H104-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher CAN No. 1 junction connector
      H104-2 (CANL) - H44-4 (CG)
      H104-4 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher CAN No. 3 junction connector
      H104-5 (CANL) - H44-4 (CG)
      H104-7 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher DLC3
      H104-8 (CANL) - H44-4 (CG)
      H104-10 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Power steering ECU assembly
      H104-11 (CANL) - H44-4 (CG)
      H104-13 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Multi-media module receiver assembly
      H104-14 (CANL) - H44-4 (CG)
      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. A003X1AE10
      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

      Disconnect the wire harness 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 Switch Condition Specified Condition Connected to
      H105-3 (CANH) - H44-4 (CG) Power switch off 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) Power switch off 200 Ω or higher Certification ECU (Smart key ECU assembly)
      H105-5 (CANL) - H44-4 (CG)
      H105-9 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Airbag sensor assembly
      H105-8 (CANL) - H44-4 (CG)
      H105-12 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Yaw rate and acceleration sensor
      H105-11 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (ECU or sensor wire) B

    B

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

    A

    REPLACE CAN NO. 2 JUNCTION CONNECTOR

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


    1. A003X81E18
      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
      *d to Power Management Control ECU

      Disconnect the instrument panel wire from 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 Connected to
      H141-5 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Main body ECU (Multiplex network body ECU)
      H141-11 (CANL) - H44-4 (CG)
      H141-6 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher CAN No. 2 junction connector
      H141-12 (CANL) - H44-4 (CG)
      H141-4 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Power management control ECU
      H141-10 (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. 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. A003X81E19
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)
      *b to ECM
      *c to Transmission Control ECU Assembly

      Disconnect the engine room main wire from 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 Connected to
      A71-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher ECM
      A71-7 (CANL) - H44-4 (CG)
      A71-2 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Transmission control ECU assembly
      A71-8 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (ECU or sensor wire) B

    B

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

    A

    REPLACE CAN NO. 1 JUNCTION CONNECTOR

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


    1. A003X81E20
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 3 Junction Connector)
      *b to CAN No. 2 Junction Connector
      *c to Combination Meter Assembly

      Disconnect the instrument panel wire from the CAN No. 3 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Connected to
      H142-5 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher CAN No. 2 junction connector
      H142-11 (CANL) - H44-4 (CG)
      H142-6 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Combination meter assembly
      H142-12 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (CAN No. 2 junction connector main line) B
      NG (Combination meter assembly main line) 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. A003X81E21
      Text in Illustration
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN No. 3 Junction Connector)
      *b to Skid Control ECU (Brake Booster with Master Cylinder Assembly)

      Disconnect the engine room main wire from the CAN No. 3 junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition Connected to
      A72-1 (CANH) - H44-4 (CG) Power switch off 200 Ω or higher Skid Control ECU (Brake booster with master cylinder assembly)
      A72-7 (CANL) - H44-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Skid control ECU branch line) B

    B

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

    A

    REPLACE CAN NO. 3 JUNCTION CONNECTOR

  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. A003YN4E26
      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
      H44-6 (CANH) - H44-4 (CG) Power switch off 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).


    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR WIRE OR CONNECTOR

    OK

    REPLACE CORRESPONDING ECU OR SENSOR