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Inspection Procedure

NOTE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (see INITIALIZATION  ).
  1. CHECK BRAKE FLUID LEVEL IN RESERVOIR 
      Fig 1: Checking Brake Fluid Level In Reservoir
      G04949613Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Check that the brake fluid level is sufficient.

      OK: Brake fluid level is proper. 

      HINT:

      • If the fluid level drops, check for a fluid leak, and repair if found.
      • Check that the brake fluid leakage (Connection between accumulator and actuator, or actuator and wheel cylinder)
      • If no leak exists, add and adjust fluid and then check that the trouble code is not output again.
    2. Check that there are no leaks from the connection between the accumulator pump and actuator.
      Fig 2: Identifying Leaks From Connection Between Accumulator Pump And Actuator
      G04949614Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      As a visual check is very difficult, perform the check with the following procedures.

      1. Bleed air from the brake actuator (see BRAKE FLUID ).
      2. Using the intelligent tester, check the data monitor of the accumulator pressure sensor.
        1. Intelligent tester

          Skid control ECU 

          SKID CONTROL ECU

          Tester Display Measurement Item/Range Normal Condition Diagnostic Note
          ACC PRESS SENS Accumulator pressure sensor / min.: 0 V, max.: 5 V Specified value: 3.2 to 4.0 V -
        2. Techstream

          Skid control ECU 

          SKID CONTROL ECU

          Tester Display Measurement Item/Range Normal Condition Diagnostic Note
          Accumulator Sensor Accumulator pressure sensor / min.:0V, max.:5V Specified value: 3.2 to 4.0 V -
      3. Wait for 30 seconds without operating the brake pedal. Then check the accumulator pressure sensor output value's change is within the specified range.

        OK: Accumulator pressure sensor output value's change is within 0.2 V. 

    NG: CHECK AND REPAIR BRAKE FLUID LEAKAGE AND ADD FLUID 

    OK: GO TO NEXT STEP 

  2. INSPECT BRAKE FLUID LEVEL WARNING SWITCH 
    1. Disconnect the A18 switch connector.
      Fig 3: Identifying A18 Switch Connector
      G04949615Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value (s) in the table below.

      HINT:

      A float is placed inside the reservoir. Its position can be changed by increasing/decreasing the level of brake fluid.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      A18-1 (GND)-A18-2 (LBL) Float up (Switch OFF) 1.84 to 2.16 kΩ
      A18-1 (GND)-A18-2 (LBL) Float down (Switch ON) Below 1 Ω

      HINT:

      If there is no problem after finishing the above check, adjust the brake fluid level to the MAX level.

    NG: REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY 

    OK: GO TO NEXT STEP 

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE FLUID LEVEL WARNING SWITCH) 
      Fig 4: Identifying A18 Switch Connector And A19 ECU Connector
      G04949616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the A19 ECU connector.
    2. Disconnect the A18 switch connector.
    3. Measure the resistance according to the value (s) in the table below.

      Standard resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Condition Specified Condition
      A19-45 (LBL)-A18-2 (LBL) Always Below 1 Ω
      A19-45 (LBL) -Body ground Always 10 kΩ or higher
      A18-1 (GND)-Body ground Always Below 1 Ω

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  4. CHECK SKID CONTROL ECU (SWITCH INPUT VOLTAGE) 
    1. Reconnect the A19 ECU connector.
      Fig 5: Identifying A18 Switch Connector
      G04949617Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the A18 switch connector.
    3. Turn the engine switch on (IG).
    4. Measure the voltage according to the value (s) in the table below.

      Standard voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester Connection Switch Condition Specified Condition
      A18-2 - Body ground Always 8 to 14 V

    NG: REPLACE SKID CONTROL ECU (See  REMOVAL   ) 

    OK: GO TO NEXT STEP 

  5. RECONFIRM DTC 
    1. Clear the DTCs (see DTC CHECK/CLEAR  ).
    2. Turn the engine switch on (IG).
    3. Check if the same DTC is 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

      Result Proceed to
      DTC (C1202/68) is output A
      DTC (C1202/68) is not output B

      HINT:

      If troubleshooting has been carried out according to the "PROBLEM SYMPTOMS TABLE", refer back to the table and proceed to the next step (see PROBLEM SYMPTOMS TABLE  ).

    B: END 

    A: GO TO NEXT STEP 

    REPLACE SKID CONTROL ECU (See  REMOVAL   ) 

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