CAN COMMUNICATION SYSTEM Check Bus 4 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 22 (CA2H) and 7 (CA2L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 22 (CA2H) and 7 (CA2L) of central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in CAN main bus lines

  • Short in CAN branch lines

  • Central gateway ECU (network gateway ECU)

  • Skid control ECU (brake actuator assembly)

  • Power steering ECU assembly

  • Front steering control ECU

  • Absorber control ECU

  • No. 8 CAN junction connector

  • No. 14 junction connector

WIRING DIAGRAM

B003UUKE02

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

Note


  • 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

  • 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

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

    DTC check procedure: Turn the ignition switch to ON and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 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

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK FOR SHORT IN CAN BUS LINES (POWER STEERING ECU ASSEMBLY)


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

    2. B003U8OC92
      *a

      Front view of wire harness connector

      (to Power Steering ECU Assembly)

      Disconnect the A19 power steering ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-4 (CA3H) - A19-6 (CA3L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE POWER STEERING ECU ASSEMBLY Click here

    NG

  2. CHECK FOR SHORT IN CAN BUS LINES (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY))


    1. Reconnect the A19 power steering ECU assembly connector.

    2. B003TFZC33
      *a

      Front view of wire harness connector

      (to Skid Control ECU (Brake Actuator Assembly))

      Disconnect the A105 skid control ECU (brake actuator assembly) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A105-36 (CA2H) - A105-37 (CA2L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) Click here

    NG

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 14 JUNCTION CONNECTOR)


    1. Reconnect the A105 skid control ECU (brake actuator assembly) connector.

    2. B003W9WC10
      *a

      Front view of wire harness connector

      (to No. 14 Junction Connector)
      *b to No. 8 CAN Junction Connector
      *c to Power Steering ECU Assembly

      Disconnect the Q57 No. 14 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      Q57-5 (CANH) - Q57-16 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 8 CAN junction connector
      Q57-6 (CANH) - Q57-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Power steering ECU assembly
      Result
      Result Proceed to
      OK A
      NG (Line to No. 8 CAN junction connector) B
      NG (Line to power steering ECU assembly) C

    A

    REPLACE NO. 14 JUNCTION CONNECTOR

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (POWER STEERING ECU ASSEMBLY - NO. 14 JUNCTION CONNECTOR)

    B

  4. CHECK FOR SHORT IN CAN BUS LINES (NO. 8 CAN JUNCTION CONNECTOR)


    1. Reconnect the Q57 No. 14 junction connector.

    2. B003W9WC12
      *a

      Front view of wire harness connector

      (to No. 8 CAN Junction Connector)
      *b to Front Steering Control ECU
      *c to Skid Control ECU (Brake Actuator Assembly)
      *d to No. 14 Junction Connector
      *e to Absorber Control ECU
      *f to Central Gateway ECU (Network Gateway ECU)

      Disconnect the K116 No. 8 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K116-1 (CANH) - K116-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Front steering control ECU
      K116-3 (CANH) - K116-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Skid control ECU (brake actuator assembly)
      K116-4 (CANH) - K116-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 14 junction connector
      K116-5 (CANH) - K116-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Absorber control ECU
      K116-6 (CANH) - K116-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      Result
      Result Proceed to
      OK A
      NG (Line to skid control ECU (brake actuator assembly)) B
      NG (Line to No. 14 junction connector) C
      NG (Line to central gateway ECU (network gateway ECU)) D
      NG (Line to ECU or sensor) E

    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY) - NO. 8 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 14 JUNCTION CONNECTOR)

    E

    CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR) Click here

    D

  5. CHECK FOR SHORT IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Reconnect the K116 No. 8 CAN junction connector.

    2. B003VK4C23
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      Disconnect the K141 central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-22 (CA2H) - K141-7 (CA2L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

  6. CHECK FOR SHORT IN CAN BUS LINES (ECU, SENSOR)


    1. Reconnect all wire harness connectors.

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

      Click here

    3. B003U8MC05
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K141-22 (CA2H) - K141-7 (CA2L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

      Tech Tips

      If the resistance becomes normal (between 54 and 69 Ω) when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

      Result
      Result
      OK
      NG

    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINES OR CONNECTOR