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Home › Lexus › 2007 › RX 400h AWD › Repair and Diagnosis › Brakes › Traction Control › Brake Control › Electronically Controlled Brake System › DTC C1365/54 Accumulator Pressure Sensor Malfunction › Inspection Procedure

Inspection Procedure

NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (See INITIALIZATION ).
  1. CHECK HARNESS AND CONNECTOR (BETWEEN SKID CONTROL ECU AND BRAKE ACTUATOR ASSEMBLY) 
    1. Disconnect the skid control ECU connector and brake actuator connector.
    2. Measure the resistance according to the value(s) in the table below.

      Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Specified Condition
      S38-8 (E) - B20-14 (E1) Below 1 Ω
      S38-9 (VCM) - B20-10 (VCM1) Below 1 Ω
      S38-21 (PAC1) - B20-15 (PACC) Below 1 Ω
      S38-31 (PCK1) - B20-12 (PCK1) Below 1 Ω
    3. Measure the resistance according to the value(s) in the table below.

    Resistance 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Specified Condition
    S38-8 (E) - Body ground 10 kΩ or higher
    S38-9 (VCM) - Body ground Below 1 Ω
    S38-21 (PAC1) - Body ground Below 1 Ω
    S38-31 (PCK1) - Body ground Below 1 Ω
    Fig 1: Identifying Skid Control ECU Connector And Brake Actuator Connector Terminal
    G05276904Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  2. INSPECT SKID CONTROL ECU (VCM TERMINAL) 
    1. Measure the voltage according to the value(s) in the table below.

      HINT:

      Measure the voltage from the back side of the connector with the connector connected to the skid control ECU.

    Voltage 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Condition Specified Condition
    S38-9 (VCM) - S38-1 (GND1) Ignition switch ON 4.75 to 5.25 V
    Fig 2: Identifying Skid Control ECU Connector And Brake Actuator Connector Terminal (VCM Terminal)
    G05276905Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

    NG: REPLACE SKID CONTROL ECU 

    OK: Go to next step 

  3. INSPECT SKID CONTROL ECU (PACC TERMINAL) 
    1. Check the auxiliary battery voltage.

      Voltage: 10 to 14 V 

    2. Depress the brake pedal to operate the pump motor, and then check that the pump motor stops.
    3. Measure the voltage according to the value(s) in the table below.

    Voltage 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Specified Condition
    S38-21 (PAC1) - S38-1 (GND1) 3.3 to 4.7 V
    Fig 3: Identifying Skid Control ECU Connector Terminal
    G05276906Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
    NOTE:
    • Do not depress the brake pedal until the pump motor stops and the voltage check is finished in order to keep the accumulator pressure.
    • Check from the back side of the connector with the connector connected to the skid control ECU.
    • Do not use a DATA LIST, as the sensor itself must be checked.

    NG: REPLACE BRAKE ACTUATOR ASSEMBLY 

    OK: Go to next step 

  4. READ VALUE OF INTELLIGENT TESTER 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the ignition switch on.
    3. Select the DATA LIST mode on the intelligent tester.

      ABS/VSC/TRAC: 

      MEASUREMENT ITEM NORMAL CONDITION CHART

      Item Measurement Item / Range (Display) Normal Condition
      ACC PRESS SENS Accumulator pressure sensor / min.: 0 V, max.: 5 V Specified value: 3.2 to 4.0 V
    4. Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the intelligent tester with the motor stopped (no braking).

      OK: Accumulator (ACC) pressure sensor voltage does not drop. 

    NG: REPLACE BRAKE ACTUATOR ASSEMBLY 

    OK: REPLACE SKID CONTROL ECU 

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