CAN COMMUNICATION SYSTEM Open in One Side of CAN Sub Bus 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.

  • Air conditioning amplifier assembly*1

  • Certification ECU (smart key ECU assembly)*2

  • Headlight leveling ECU assembly*3

WIRING DIAGRAM

A003HCLE01

INSPECTION PROCEDURE

Note

For vehicles with a smart entry and start system:

Before replacing the certification ECU (smart key ECU assembly), refer to the smart entry and start system Click here.

Tech Tips


  • Perform the following inspection for the ECUs (sensors) which are not 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 combination meter assembly and ECM, as they are the end parts of the circuit. If removed, CAN communication will not be possible.

  • The open circuit confirmation of the combination meter assembly, ECM 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 the CAN branch wire.

PROCEDURE


  1. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (CERTIFICATION ECU)

    Note

    For vehicles without a smart entry and start system, go to "Check for Open in One Side of CAN Branch Wire (Headlight Leveling ECU Assembly)".


    1. Disconnect the B76 certification ECU (smart key ECU assembly) connector.

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

      Result
      Result Proceed to
      "Certification (Smart)" not displayed on the intelligent tester. A
      Several ECUs and sensors in addition to "Certification (Smart)" not displayed on the intelligent tester. B

    B

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

    A

  2. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (CERTIFICATION ECU CAN BRANCH WIRE)


    1. A003E8CE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Certification ECU [Smart Key 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:

      For vehicles with an airbag system:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS 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
      B76-40 (CANH) - B76-18 (CANL) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (CERTIFICATION ECU)

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

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

    Note

    For vehicles with a halogen headlight, go to "Check for Open in One Side of CAN Branch Wire (Air Conditioning Amplifier Assembly CAN Branch Wire)".


    1. Disconnect the A39 headlight leveling ECU assembly connector.

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

      Result
      Result Proceed to
      "Headlight swivel (AFS)" not displayed on the intelligent tester. A
      Several ECUs and sensors in addition to "Headlight swivel (AFS)" not displayed on the intelligent tester. B

    B

    CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIR CONDITIONING AMPLIFIER ASSEMBLY CAN BRANCH WIRE) Click here

    A

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


    1. A003F0VE17
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Headlight Leveling 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:

      For vehicles with an airbag system:

      Wait at least 90 seconds after disconnecting the cable from the negative (-) battery terminal to disable the SRS 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
      A39-6 (CANH) - A39-7 (CANL) Ignition switch off 54 to 69 Ω
      Result
      Result Proceed to
      OK (for LHD) A
      OK (for RHD) B
      NG C

    B

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

    C

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (HEADLIGHT LEVELING ECU ASSEMBLY)

    A

    REPLACE HEADLIGHT LEVELING ECU ASSEMBLY Click here

  5. CHECK FOR OPEN IN ONE SIDE OF CAN BRANCH WIRE (AIR CONDITIONING AMPLIFIER ASSEMBLY CAN BRANCH WIRE)

    Note

    For vehicles without an air conditioning system or with 5L-E engine type, go to "How to Proceed with Troubleshooting".


    1. A003G39E03
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

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

      CAUTION:

      For vehicles with an airbag system:

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

      Note

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

    2. Disconnect the air conditioning amplifier assembly connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      H18-10 (CANH) - H18-11 (CANL) Ignition switch off 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE OR CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY)

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here