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Home >> Lexus >> 2008 >> GS 450h >> 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 brake actuator, perform initialization of linear solenoid valve and calibration (see INITIALIZATION  ).

HINT:

When C1364/61 is output together with C1341/62, C1342/63, C1343/64 and 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 from the front and rear brake systems (see BLEEDING ).
  3. CHECK WIRE HARNESS (SKID CONTROL ECU - BODY GROUND) 
    1. Disconnect the A13 and A15 ECU connectors.
    2. Measure the resistance according to the value(s) in the table below.
      Fig 1: Identifying A13 And A15 ECU Connectors
      G05816363Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard resistance 

      STANDARD RESISTANCE SPECIFICATION

      Tester Connection Specified Condition
      A13-3 (FRA+) - Body ground 10 kΩ or higher
      A13-18 (FRA-) - Body ground 10 kΩ or higher
      A13-4 (FRR+) - Body ground 10 kΩ or higher
      A13-17 (FRR-) - Body ground 10 kΩ or higher
      A13-33 (RLA+) - Body ground 10 kΩ or higher
      A13-35 (RLA-) - Body ground 10 kΩ or higher
      A13-34 (RLR+) - Body ground 10 kΩ or higher
      A13-19 (RLR-) - Body ground 10 kΩ or higher
      A15-3 (FLA+) - Body ground 10 kΩ or higher
      A15-18 (FLA-) - Body ground 10 kΩ or higher
      A15-4 (FLR+) - Body ground 10 kΩ or higher
      A15-17 (FLR-) - Body ground 10 kΩ or higher
      A15-33 (RRA+) - Body ground 10 kΩ or higher
      A15-20 (RRA-) - Body ground 10 kΩ or higher
      A15-34 (RRR+) - Body ground 10 kΩ or higher
      A15-36 (RRR-) - Body ground 10 kΩ or higher

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. READ VALUE USING TECHSTREAM (WHEEL CYLINDER PRESSURE SENSOR) 
    1. Connect the pedal effort gauge.
    2. Install the LSPV gauge (SST) and perform bleeding (see BLEEDING ).

      SST 09709-29018 

    3. Connect the Techstream to the DLC3.
    4. Select the Data List mode on the Techstream.

      ABS/VSC/TRAC: 

      TESTER DISPLAY REFERENCE CHART

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR W/C Sensor FR wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V -
      FL W/C Sensor FL wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V -
      RR W/C Sensor RR wheel cylinder pressure sensor / min.: 0 V, max.: 5 V When brake pedal is released: 0.3 to 0.9 V -
      RL W/C Sensor RL 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 system control.

      Standard voltage: 

      Front wheel cylinder pressure sensor 

      FLUID PRESSURE SPECIFICATION

      Fluid Pressure MPa (kgf/cm2 , psi) FR W/C Sensor (Data List) FL W/C Sensor (Data List)
      3.2 (32.6, 464) 1.0 to 1.3 V 1.0 to 1.3 V
      7.0 (71.4,1016) 1.75 to 2.05 V 1.75 to 2.05 V
      8.3 (84.6,1203) 2.05 to 2.35 V 2.05 to 2.35 V

      Rear wheel cylinder pressure sensor 

      FLUID PRESSURE SPECIFICATION

      Fluid Pressure MPa (kgf/cm2 , psi) RR W/C Sensor (Data List) RL W/C Sensor (Data List)
      3.1 (31.6,449) 1.0 to 1.3 V 1.0 to 1.3 V
      4.0 (40.8, 580) 1.15 to 1.45 V 1.15 to 1.45 V

    NG: REPLACE BRAKE ACTUATOR ASSEMBLY  (See REMOVAL  )

    OK: Go to next step 

  5. 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 system control.
      • If the brake pedal stroke sensor connector is disconnected, the fail-safe function will prohibit electronically controlled brake system control.
      • As the Active Test does not prohibit electronically controlled brake system control when the vehicle is running, disconnect the stroke sensor connector, and then carry out the inspection.
      • Disc wear can be checked by measuring the disc thickness.

    NG: REPLACE BRAKE DISC  (See FRONT BRAKE )

    OK: Go to next step 

  6. RECONFIRM DTC 
    1. Clear the DTCs (see DTC CHECK/CLEAR  ).
    2. Repeat the braking test under malfunction conditions recreated based on the Freeze Frame Data (see FREEZE FRAME DATA  ).
    3. Check if the same DTCs are recorded (see DTC CHECK/CLEAR  ).

      HINT:

      Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

      Result 

      RESULT REFERENCE

      Condition Proceed to
      DTCs (C1341/62, C1342/63, C1343/64 and C1344/65) are not output A
      DTCs (C1341/62, C1342/63, C1343/64 and C1344/65) are output B

    B: REPLACE BRAKE ACTUATOR ASSEMBLY  (See REMOVAL  )

    A: END 

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