CAN COMMUNICATION SYSTEM(for LHD) Check Bus 2 Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus wires and GND when no resistance exists between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to GND in bus 2 CAN main wires

  • Short to GND in bus 2 CAN branch wires

  • Central gateway ECU (network gateway ECU)

  • Combination meter assembly

  • Stereo component equalizer assembly

  • Certification ECU (smart key ECU assembly)

  • Airbag ECU assembly

  • Combination meter mirror ECU*1

  • Power steering ECU assembly

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

  • Air conditioning amplifier assembly

  • Brake actuator assembly (skid control ECU)

  • Headlight light control ECU sub-assembly LH

  • Yaw rate and acceleration sensor (yaw rate sensor)

  • Main body ECU (multiplex network body ECU)

  • Parking brake ECU assembly

  • Torque vectoring differential ECU assembly

  • ECM

  • No. 2 CAN junction connector

  • No. 3 CAN junction connector

  • No. 9 CAN junction connector

WIRING DIAGRAM

B002D8GE02
B002EWOE02
B002DMVE02
*a Parking Brake ECU Assembly
*b No. 9 CAN Junction Connector
*c Torque Vectoring Differential ECU Assembly

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the engine 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 (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) 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 engine switch on (IG), wait at least 60 seconds, and then drive the vehicle at a speed of 40 km/h (25 mph) or more for 5 minutes or more.

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

    Click here

  • Before replacing the ECM, certification ECU (smart key ECU assembly) or main body ECU (multiplex network body ECU), refer to Service Bulletin.

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 SHORT TO GND IN CAN BUS WIRE (ECM - NO. 9 CAN JUNCTION CONNECTOR)


    1. B002DAUC02
      *a

      Front view of wire harness connector

      (to ECM)
      *b Front view of DLC3

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

    2. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A13-13 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A13-14 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the A13 ECM connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (COMBINATION METER ASSEMBLY - NO. 3 CAN JUNCTION CONNECTOR)


    1. B002C6QC02
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)
      *b Front view of DLC3

      Disconnect the combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K33-29 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K33-30 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the K33 combination meter assembly connector.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 3 CAN JUNCTION CONNECTOR)


    1. B002C8VC34
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))
      *b Front view of DLC3

      Disconnect the central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K66-18 (CA4H) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-17 (CA4L) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

  6. CONNECT CONNECTOR


    1. Reconnect the K66 central gateway ECU (network gateway ECU) connector.

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 9 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 9 CAN junction connectors.

      B002DK9C02
      *1 No. 9 CAN Junction Connector - -
      *a

      Rear view of wire harness connector

      (to No. 9 CAN Junction Connector)

      		 *b Front view of DLC3
      Code Color (CANH Side) Color (CANL Side) Connect to
      U48 B W Parking Brake ECU Assembly
      U49 R W ECM
      U50 G W No. 2 CAN Junction Connector
      U51 L W Torque Vectoring Differential ECU Assembly

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      U48-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Parking brake ECU assembly
      U48-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      U49-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher ECM
      U49-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      U50-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction connector
      U50-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      U51-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Torque vectoring differential ECU assembly
      U51-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Result Proceed to
      OK A
      NG (ECM CAN main wire) B
      NG (No. 3 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wire) D

    A

    REPLACE NO. 9 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 9 CAN JUNCTION CONNECTOR - ECM)

    D

    GO TO STEP 12 Click here

    C

  8. CONNECT CONNECTOR


    1. Reconnect the U48, U49, U50 and U51 No. 9 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT

  9. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 2 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 2 CAN junction connectors.

      B002ES1C45
      *1 No. 2 CAN Junction Connector - -
      *a

      Rear view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b Front view of DLC3
      Code Color (CANH Side) Color (CANL Side) Connect to
      K82 B W No. 3 CAN Junction Connector
      K83 R W Spiral Cable with Sensor Sub-assembly (Steering Angle Sensor)
      K84 G W No. 9 CAN Junction Connector
      K85 L W Brake Actuator Assembly (Skid Control ECU)
      K86 Y W Air Conditioning Amplifier Assembly
      K87 V W Yaw Rate and Acceleration Sensor (Yaw Rate Sensor)
      K88 P W Headlight Light Control ECU Sub-assembly LH
      K89 BE W Main Body ECU (Multiplex Network Body ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K82-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 3 CAN junction connector
      K82-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K83-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Spiral cable with sensor sub-assembly (steering angle sensor)
      K83-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K84-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 9 CAN junction connector
      K84-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K85-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Brake actuator assembly (skid control ECU)
      K85-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K86-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      K86-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K87-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate and acceleration sensor (yaw rate sensor)
      K87-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K88-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Headlight light control ECU sub-assembly LH
      K88-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K89-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      K89-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Result Proceed to
      OK A
      NG (No. 9 CAN junction connector CAN main wire) B
      NG (No. 3 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 9 CAN JUNCTION CONNECTOR)

    D

    GO TO STEP 12 Click here

    C

  10. CONNECT CONNECTOR


    1. Reconnect the K82, K83, K84, K85, K86, K87, K88 and K89 No. 2 CAN junction connectors.

      Result
      Proceed to
      NEXT

    NEXT

  11. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 3 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 3 CAN junction connectors.

      B002ES1C46
      *1 No. 3 CAN Junction Connector - -
      *a

      Rear view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b Front view of DLC3
      Code Color (CANH Side) Color (CANL Side) Connect to
      K90 B W No. 2 CAN Junction Connector
      K91 R W Stereo Component Equalizer Assembly
      K92 G W Central Gateway ECU (Network Gateway ECU)
      K93 L W Power Steering ECU Assembly
      K94 Y W Airbag ECU Assembly
      K95 V W Combination Meter Mirror ECU*1
      K96 P W Certification ECU (Smart Key ECU Assembly)
      K97 BE W Combination Meter Assembly

      • *1: w/ Headup Display

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K90-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction connector
      K90-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K91-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Stereo component equalizer assembly
      K91-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K92-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K92-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K93-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      K93-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K94-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly
      K94-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K95-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Combination meter mirror ECU*1
      K95-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K96-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      K96-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K97-1 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Combination meter assembly
      K97-2 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • *1: w/ Headup Display

      Result
      Result Proceed to
      OK A
      NG (central gateway ECU (network gateway ECU) CAN branch wire) B
      NG (No. 3 CAN junction connector CAN main wire) C
      NG (combination meter assembly CAN main wire) D
      NG (ECU or sensor CAN branch wires) E

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

    C

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

    D

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    E

  12. CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)


    1. B002ELMC46
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))
      *b Front view of DLC3

      Reconnect the CAN junction connector.

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short to GND is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K66-18 (CA4H) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-17 (CA4L) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      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.

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BRANCH WIRES OR CONNECTOR

    NG

    REPLACE CORRESPONDING ECU OR SENSOR