CAN COMMUNICATION SYSTEM(for LHD) Skid Control ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
Skid Control ECU Communication Stop Mode

Either condition is met:


  • "Skid Control (ABS/VSC/TRAC)" is not displayed on "CAN Bus Check".

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  • Communication system DTCs (DTCs that start with U) that are output correspond to "Skid Control ECU Communication Stop Mode" in "DTC Combination Table".

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  • Power source or inside brake actuator assembly (skid control ECU)

  • Brake actuator assembly (skid control ECU) CAN branch wire or connector

  • Brake actuator assembly (skid control ECU)

  • Engine stop and start ECU*
*: w/ Stop and Start System

WIRING DIAGRAM

A01KBDUE01
A01KDDTE01

CAUTION / NOTICE / HINT

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.

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  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, 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 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.

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  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.

  • DTC check procedure: Turn the ignition switch to ON and wait at least 60 seconds.

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

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Tech Tips


  • Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • 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 OPEN IN CAN BUS WIRE (SKID CONTROL ECU CAN BRANCH WIRE)


    1. A01KBCYC24
      *A w/ Vehicle Stability Control System
      *B w/o Vehicle Stability Control System
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly [Skid Control ECU])

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

    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
      w/ Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A64-25 (CANH) - A64-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      w/o Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A63-25 (CANH) - A63-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BATTERY AND BODY GROUND)


    1. A01KBCYC25
      *A w/ Vehicle Stability Control System
      *B w/o Vehicle Stability Control System
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly [Skid Control ECU])

      Connect the cable to the negative (-) battery terminal.

      Note

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

      Click here

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

      Standard Voltage
      w/ Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A64-12 (+BS) - Body ground Always 11 to 14 V
      A64-24 (BM) - Body ground Always 11 to 14 V
      w/o Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A63-12 (+BS) - Body ground Always 11 to 14 V
      A63-24 (+BM) - Body ground Always 11 to 14 V

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

      Standard Resistance
      w/ Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A64-1 (GND1) - Body ground Always Below 1 Ω
      A64-13 (GND2) - Body ground Always Below 1 Ω
      w/o Vehicle Stability Control System
      Tester Connection Condition Specified Condition
      A63-1 (GND1) - Body ground Always Below 1 Ω
      A63-13 (GND2) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BATTERY)


    1. A01KBCYC26
      *A w/ Vehicle Stability Control System
      *B w/o Vehicle Stability Control System
      *a

      Front view of wire harness connector

      (to Brake Actuator Assembly [Skid Control ECU])

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

      Standard Voltage
      w/ Vehicle Stability Control System
      Tester Connection Switch Condition Specified Condition
      A64-34 (IG1) - Body ground Ignition switch ON 11 to 14 V
      w/o Vehicle Stability Control System
      Tester Connection Switch Condition Specified Condition
      A63-34 (IG1) - Body ground Ignition switch ON 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (w/o Vehicle Stability Control System) B
      NG (w/ Vehicle Stability Control System and w/o Stop and Start System)
      NG (w/ Vehicle Stability Control System and w/ Stop and Start System) C

    A

    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) w/ Vehicle Stability Control System: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY (SKID CONTROL ECU) w/o Vehicle Stability Control System: Click here

    B

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    C

  4. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - ENGINE STOP AND START ECU)


    1. Disconnect the G87 engine stop and start ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A64-34 (IG1) - G87-12 (IGO1) Always Below 1 Ω
      A64-34 (IG1) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ENGINE STOP AND START ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR