ANTI-LOCK BRAKE SYSTEM, Diagnostic DTC:U0073

DTC Code DTC Name
U0073 Control Module Communication Bus OFF

DESCRIPTION

The skid control ECU (brake actuator assembly) receives signals from the ECM via the CAN communication system.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

U0073

Control Module Communication Bus OFF

The condition that the bus OFF state occurs once or more within 0.1 seconds occurs 10 times in succession while the voltage at the IG1 terminal is between 10 and 17.4 V. (Sent signals cannot be received.)

CAN communication system

PROCEDURE

  1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

    1. Using the GTS, check for any momentary interruption in the wire harness and connector corresponding to a DTC.

      Click here

    Chassis > ABS/VSC/TRC > Data List

    Tester Display

    Measurement Item

    Range

    Normal Condition

    Diagnostic Note

    EFI Communication Open

    ECM communication open detection

    Normal or Error

    Normal

    Error: Momentary interruption

    Chassis > ABS/VSC/TRC > Data List

    Tester Display

    EFI Communication Open
    Tip:

    Perform the above inspection before removing the sensor and connector.

    Result

    Proceed to

    There is a constant open circuit

    There are no momentary interruptions

    There are momentary interruptions
    There are no momentary interruptions

    RECONFIRM DTCClick here

    There are momentary interruptions

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    There is a constant open circuit

  2. CHECK IF EACH SENSOR AND ECM CONNECTOR IS SECURELY CONNECTED

    1. Turn the ignition switch off.

    2. Check if each sensor or ECM connector is securely connected.

      OK

      Each connector is securely connected.

    Result

    Proceed to

    OK

    NG
    NG

    CONNECT CONNECTOR TO EACH SENSOR OR ECM CORRECTLY

    OK

  3. RECONFIRM DTC

    1. Turn the ignition switch off.

    2. Record the output DTCs (for ABS and CAN communication).

      for ABS:Click here

      for CAN communication system:Click hereClick hereClick here

      Chassis > ABS/VSC/TRC > Trouble Codes

      Tip:

      If the CAN communication system DTC and the relevant sensor DTCs are output simultaneously, troubleshoot the relevant sensor DTCs (for ABS) after the CAN communication system returns to normal.

      Result

      Result

      Proceed to

      DTC (relating to CAN communication system) is output

      A

      DTC (relating to ABS) is output

      B

      DTC is not output

      C
    A

    CHECK CAN COMMUNICATION SYSTEM

    Click here

    B

    REPAIR CIRCUIT INDICATED BY OUTPUT DTC

    Click here

    C

    USE SIMULATION METHOD TO CHECK

    Click hereClick hereClick hereClick here

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR

    1. Turn the ignition switch off.

    2. Repair or replace the harness or connector.

    3. Check for any momentary interruption between the skid control ECU (brake actuator assembly) and each sensor or ECM.

      Click here

    4. Check that there is no momentary interruption.

    Result

    Proceed to

    NEXT
    NEXT

  5. RECONFIRM DTC

    1. Turn the ignition switch off.

    2. Clear the DTCs.

      Click here

    3. Start the engine.

    4. Drive the vehicle at a speed of 15 km/h (9 mph) or more and turn the steering wheel to the right and left.

    5. Check that no CAN communication system DTC is output.

      Click hereClick here

    6. If ABS DTCs are output, record them.

      Chassis > ABS/VSC/TRC > Trouble Codes

    Chassis > ABS/VSC/TRC > Clear DTCs

    Tip:

    The CAN communication system must be normal when repairing each sensor DTC (for ABS).

    Result

    Proceed to

    DTC is not output

    DTC is output (relating to ABS)

    DTC is output (relating to CAN communication system)
    DTC is not output

    END

    DTC is output (relating to ABS)

    REPAIR CIRCUIT INDICATED BY OUTPUT DTC

    Click here

    DTC is output (relating to CAN communication system)

    CHECK CAN COMMUNICATION SYSTEM

    Click here