CAN COMMUNICATION SYSTEM Open in One Side of CAN Branch Line

DESCRIPTION

If 2 or more ECUs and/or sensors do not appear on the intelligent tester "Bus Check" screen, one side of the CAN branch wire may be open (one side of the CANH [CAN branch wire]/CANL [CAN branch wire] of the ECU and/or sensor is open).

Symptom Trouble Area
2 or more ECUs and/or sensors do not appear on the intelligent tester "Bus Check" screen.

  • Electric vehicle control ECU assembly

  • Airbag ECU assembly

  • Brake actuator assembly (skid control ECU)

  • CAN branch wire or connector

WIRING DIAGRAM

A01CIWYE02
A01CI8GE02

INSPECTION PROCEDURE

Note


  • The vehicle is equipped with an SRS (Supplemental Restraint System) which includes components such as airbags. Before servicing (including removal or installation of parts), be sure to read the Precaution in the SRS Click here.

  • After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work Click here.

Tech Tips


  • Perform the following inspection for the ECUs (sensors) which are displayed on the intelligent tester. If a malfunction cannot be identified, perform the following inspections for the ECUs (sensors) connected to the CAN communication system.

  • Do not remove the ECM and No. 5 junction connector as they are the end parts of the circuit. If removed, CAN communication will not be possible.

  • The open circuit confirmation of the ECM, No. 5 junction connector and CAN main wire is performed in the Check CAN Bus Line procedure of "How to Proceed with Troubleshooting". This inspection only has procedures for checking for an open circuit on one side of a CAN branch wire.

PROCEDURE


  1. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (ELECTRIC VEHICLE CONTROL ECU ASSEMBLY)


    1. Disconnect the E41 electric vehicle control ECU assembly connector.

    2. Select "Bus Check" on the intelligent tester Click here.

      Result
      Result Proceed to
      "Electric Vehicle Control" is not displayed on the intelligent tester A
      Several ECUs and sensors in addition to "Electric Vehicle Control" are displayed on the intelligent tester B

    B

    CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIRBAG ECU ASSEMBLY) Click here

    A

  2. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (ELECTRIC VEHICLE CONTROL ECU ASSEMBLY CAN BRANCH WIRE)


    1. A01CGU6E08
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Electric Vehicle Control ECU Assembly)

      Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and the CAN branch wire.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the airbag system.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      E41-4 (CANH) - E41-5 (CANL) Ignition switch off 54 to 69 Ω
      E41-8 (CANP) - E41-9 (CANN) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (ELECTRIC VEHICLE CONTROL ECU ASSEMBLY)

    OK

    REPLACE ELECTRIC VEHICLE CONTROL ECU ASSEMBLY Click here

  3. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIRBAG ECU ASSEMBLY)


    1. Disconnect the A30 airbag ECU assembly connector Click here.

    2. Select "Bus Check" on the intelligent tester Click here.

      Result
      Result Proceed to
      "Airbag" is not displayed on the intelligent tester A
      Several ECUs and sensors in addition to "Airbag" are displayed on the intelligent tester B

    B

    CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (SKID CONTROL ECU CAN BRANCH WIRE) Click here

    A

  4. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIRBAG ECU ASSEMBLY CAN BRANCH WIRE)


    1. A01CIBIE06
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Airbag ECU Assembly)

      Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and the CAN branch wire.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the airbag system.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A30-18 (CANH) - A30-10 (CANL) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (AIRBAG ECU ASSEMBLY)

    OK

    REPLACE AIRBAG ECU ASSEMBLY Click here

  5. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (SKID CONTROL ECU CAN BRANCH WIRE)


    1. A01CGRAE48
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly [Skid Control ECU])

      Disconnect the cable from the negative (-) battery terminal before measuring the resistances of the CAN main wire and the CAN branch wire.

      CAUTION:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the airbag system.

      Note

      When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.

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

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      B9-15 (CH) - B9-26 (CL-) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (SKID CONTROL ECU)

    OK

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) Click here