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Home >> Lexus >> 2007 >> RX 400h FWD >> Repair and Diagnosis >> Brakes >> Traction Control >> Brake Control >> Electronically Controlled Brake System >> DTC C1341/62 Front Hydraulic System RH Malfunction; DTC C1342/63 Front Hydraulic System LH Malfunction; DTC C1343/64 Rear Hydraulic System RH Malfunction; DTC C1344/65 Rear Hydraulic System LH Malfunction >> Inspection Procedure

Inspection Procedure

NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (See INITIALIZATION ).

HINT:

When C1364/61 is output together with C1341/62, C1342/63, C1343/64 or C1344/65, inspect and repair the trouble areas indicated by C1364/61 first.

  1. CHECK BRAKE FLUID LEAKAGE 
    1. Check that there is no fluid leakage in the brake line between the brake actuator and the wheel cylinder which is the cause of DTCs.
    2. Check that the brake is not dragging.

      OK: There is no fluid leakage or dragging. 

    NG: REPAIR OR REPLACE APPLICABLE PART 

    OK: Go to next step 

  2. PERFORM AIR BLEED 
    1. Bleed the air out of the front and rear systems (See BRAKE FLUID ).
  3. RECONFIRM DTC 
    1. Clear the DTCs (See DTC CHECK / CLEAR ).
    2. Turn the ignition switch on.
    3. Check the same DTCs are recorded (See DTC CHECK / CLEAR ).

    Result 

    RESULT CHART

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

    HINT:

    DTC may be stored if foreign matter or air enters the solenoid valve.

    B: END 

    A: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (BETWEEN SKID CONTROL ECU AND BRAKE ACTUATOR ASSEMBLY) 
    1. Disconnect the skid control ECU connectors and brake actuator connector.
      Fig 1: Identifying Skid Control ECU Connectors And Brake Actuator Connector
      G05276903Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
    2. Measure the resistance according to the value(s) in the table below.

      Resistance 

      TESTER CONNECTION SPECIFIED CONDITION CHART

      Tester Connection Tester Connection
      S38-6 (FRA-) - B20-43 (SLAFR-) Below 1 Ω
      S38-7 (FRA+) - B20-44 (SLAFR+) Below 1 Ω
      S38-26 (RLR-) - B20-26 (SLRRL-) Below 1 Ω
      S38-16 (RLR+) - B20-25 (SLRRL+) Below 1 Ω
      S38-27 (RLA-) - B20-42 (SLARL-) Below 1 Ω
      S38-15 (RLA+) - B20-41 (SLARL+) Below 1 Ω
      S41-18 (RRR-) - B20-24 (SLRRR-) Below 1 Ω
      S41-20 (RRR+) - B20-23 (SLRRR+) Below 1 Ω
      S41-9 (RRA-) - B20-40 (SLARR-) Below 1 Ω
      S41-19 (RRA+) - B20-39 (SLARR+) Below 1 Ω
      S41-26 (FLR-) - B20-22 (SLRFL-) Below 1 Ω
      S41-8 (FLR+) - B20-21 (SLRFL+) Below 1 Ω
      S41-2 (FLA-) - B20-38 (SLAFL-) Below 1 Ω
      S41-1 (FLA+) - B20-35 (SLAFL+) Below 1 Ω
      S38-34 (FRR-) - B20-27 (SLRFR-) Below 1 Ω
      S38-17 (FRR+) - B20-28 (SLRFR+) Below 1 Ω
    3. Measure the resistance according to the value(s) in the table below.

    Resistance 

    TESTER CONNECTION SPECIFIED CONDITION CHART

    Tester Connection Tester Connection
    S38-6 (FRA-) - Body ground 10 kΩ or higher
    S38-7 (FRA+) - Body ground 10 kΩ or higher
    S38-15 (RLA+) - Body ground 10 kΩ or higher
    S38-16 (RLR+) - Body ground 10 kΩ or higher
    S38-17 (FRR+) - Body ground 10 kΩ or higher
    S38-26 (RLR-) - Body ground 10 kΩ or higher
    S38-27 (RLA-) - Body ground 10 kΩ or higher
    S38-34 (FRR-) - Body ground 10 kΩ or higher
    S41-1 (FLA+) - Body ground 10 kΩ or higher
    S41-2 (FLA-) - Body ground 10 kΩ or higher
    S41-8 (FLR+) - Body ground 10 kΩ or higher
    S41-9 (RRA-) - Body ground 10 kΩ or higher
    S41-18 (RRR-) - Body ground 10 kΩ or higher
    S41-19 (RRA+) - Body ground 10 kΩ or higher
    S41-20 (RRR+) - Body ground 10 kΩ or higher
    S41-26 (FLR-) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. READ VALUE OF INTELLIGENT TESTER (WHEEL CYLINDER PRESSURE SENSOR) 
    1. Connect the pedal effort gauge.
    2. Install the LSPV gauge (SST) and bleed air (See ON-VEHICLE INSPECTION ).

      SST 09709-29018 

    3. Connect the intelligent tester to the DLC3.
    4. Select the DATA LIST mode on the intelligent tester.

      ABS/VSC/TRAC: 

      MEASUREMENT ITEM NORMAL CONDITION CHART

      Item Measurement Item / Range (Display) Normal Condition
      FR W/C SENS Front right wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V
      FL W/C SENS Front left wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V
      RR W/C SENS Rear right wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V
      RL W/C SENS Rear left wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V
    5. Check the output value of the wheel cylinder pressure at each fluid pressure during the Electronically Controlled Brake control.

    Voltage: 

    Front wheel cylinder pressure sensor 

    VOLTAGE SPECIFICATION CHART

    Fluid Pressure MPa (kgf/cm2 , psi) FR PRESS SENS (DATA-LIST) FL PRESS SENS (DATA-LIST)
    2.6 (26.5, 376.9) 0.85 to 1.15 V 0.85 to 1.15 V
    6.3 (64.3, 89.6) 1.6 to 1.9 V 1.6 to 1.9 V
    8.1 (82.6, 1174.8) 1.95 to 2.25 V 1.95 to 2.25 V
    8.2 (83.6, 1189.0) 2.0 to 2.3 V 2.0 to 2.3 V

    Rear wheel cylinder pressure sensor 

    VOLTAGE SPECIFICATION CHART

    Fluid Pressure MPa (kgf/cm2 , psi) RR PRESS SENS (DATA-LIST) RL PRESS SENS (DATA-LIST)
    2.7 (27.5, 83.4) 0.85 to 1.15 V 0.85 to 1.15 V
    5.0 (51.0, 725.4) 1.35 to 1.65 V 1.35 to 1.65 V

    NG: REPLACE BRAKE ACTUATOR ASSEMBLY 

    OK: Go to next step 

  6. CHECK BRAKE DISC 
    1. Disconnect the brake pedal stroke sensor connector.
    2. Carry out the running and braking test according to freeze frame data or customer problem analysis. Check the brake line pressure vibration caused due to uneven wear of the disc according to brake pedal vibration.

      OK: Brake pedal does not vibrate during braking. 

      HINT:

      • The brake pedal does not kick back due to wheel cylinder piston vibration during Electronically Controlled Brake control.
      • If the brake pedal stroke sensor connector is disconnected, the fail-safe function prohibits Electronically Controlled Brake control.
      • The active test does not prohibit Electronically Controlled Brake control when the vehicle is running, so disconnect the stroke sensor connector and carry out inspection.
      • Disc wear can be checked by measuring the disc thickness.

    NG: REPLACE BRAKE DISC 

    OK: REPLACE BRAKE ACTUATOR ASSEMBLY 

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