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Home › Lexus › 2007 › GX 470 › Repair and Diagnosis › Brakes › Traction Control › Brake Control › Vehicle Stability Control System › DTC C1254/54: Pressure Switch Circuit › Inspection Procedure

Inspection Procedure

NOTE: When replacing the master cylinder solenoid, perform zero point calibration (See CALIBRATION  ).
  1. READ VALUE OF INTELLIGENT TESTER (ACCUMULATOR PRESSURE SENSOR) 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the ignition switch off.
    3. Depress the brake pedal more than 20 times.
    4. Turn the ignition switch to the ON position and push the intelligent tester main switch ON.
    5. Select "DATA LIST" mode on the intelligent tester.
      DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      ACC PRESS SENS Accumulator pressure sensor reading / min.: 0 V, max.: 5 V 3.58 to 5 V If the value is constant regardless of pump operation, accumulator pressure sensor malfunction is suspected.
    6. Check the accumulator output value.

    Result 

    RESULT TABLE

    Condition Proceed to
    Output value is within the "Normal Condition" range A
    Output value is out of the "Normal Condition" range B
    Output value is constant regardless of pump operation B

    B: REPLACE MASTER CYLINDER SOLENOID 

    A: Go to Next Step 

  2. READ VALUE OF INTELLIGENT TESTER (MASTER CYLINDER PRESSURE SENSOR) 
    1. Turn the ignition switch off.
    2. Depress the brake pedal more than 20 times.
    3. Install the brake pedal effort gauge (SST), and bleed air.

      SST 09709-29018 

    4. Turn the ignition switch to the ON position and push the intelligent tester main switch ON.
    5. Select "DATA LIST" mode on the intelligent tester.
      DATA LIST

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      MAS CYL PRES 1 Master cylinder pressure sensor 1 reading / min.: 0 V, max.: 5 V 0.3 to 1.8 V
      With pedal effort of 49 N (5 kgf, 11 in.*lbf)      		 Front brake pressure: 930 to 2130 kPa (9.5 to 21.7 kgf/cm2 , 135 to 309 psi)
    6. Check that the master cylinder pressure sensor's output value is normal.

      OK: Master cylinder pressure sensor value is normal. 

    NG: REPLACE MASTER CYLINDER SOLENOID 

    OK: Go to Next Step 

  3. RECONFIRM DTC 
    1. Clear the DTC (See DTC CHECK/CLEAR  ).
    2. Turn the ignition switch off.
    3. Depress the brake pedal more than 20 times.
    4. Turn the ignition switch to the ON position.
    5. Wait until the pump motor stops.
    6. Depress the brake pedal and release it.
    7. Wait for 25 minutes.
    8. Check if the same DTC is detected (See DTC CHECK/CLEAR  ).

    Result 

    RESULT TABLE

    Condition Proceed to
    DTC is output A
    DTC is not output B

    B: END 

    A: REPLACE MASTER CYLINDER SOLENOID 

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