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Home >> Lexus >> 2008 >> RX 400h AWD >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control >> Electronically Controlled Brake System >> DTC C1365/54 Accumulator Pressure Sensor Malfunction >> Inspection Procedure
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

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 

      RESISTANCE SPECIFICATION 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 

      RESISTANCE SPECIFICATION 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
      4. Fig 1: Identifying Skid Control ECU Connector And Brake Actuator Connector
      G05276904Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    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 

      VOLTAGE SPECIFICATION CHART

      Tester Connection Condition Specified Condition
      S38-9 (VCM) - S38-1 (GND1) Ignition switch ON 4.75 to 5.25 V
      2. Fig 2: Identifying S38 Skid Control ECU Connector Terminals
      G05276905Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    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 

      VOLTAGE SPECIFICATION CHART

      Tester Connection Specified Condition
      S38-21 (PAC1) - S38-1 (GND1) 3.3 to 4.7 V
      Fig 3: Identifying S38 Skid Control ECU Connector Terminal
      G05276906Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      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 TECHSTREAM (ACCUMULATOR PRESSURE SENSOR) 
    1. Connect Techstream to the DLC3.
    2. Turn the ignition switch on.
    3. Select the Data List mode on Techstream.

      ABS/VSC/TRAC: 

      ABS/VSC/TRAC DATA LIST REFERENCE

      Tester Display Measurement Item/Range Normal Condition
      Accumulator Sensor 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 Techstream 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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