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Inspection Procedure

NOTE: When replacing the skid control ECU, perform the following operations:
  • Initialization of linear solenoid valve and calibration (see INITIALIZATION  )
  • Yaw rate and acceleration sensor zero point calibration (see CALIBRATION  )
  1. CHECK BRAKE FLUID LEVEL IN RESERVOIR 
    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.
        Fig 1: Checking Brake Fluid Level In Reservoir
        G04949613Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Check that there are no leaks from the connection between the accumulator pump and actuator.

      HINT:

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

      Fig 2: Checking Data Monitor Of Accumulator Pressure Sensor And Intelligent Tester
      G04949614Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Bleed air from the brake actuator (see REPLACEMENT )
      2. Using the Intelligent tester or Techstream, check the data monitor of the accumulator pressure sensor.
        1. Intelligent tester

          ABS/VSC: 

          ABS/VSC REFERENCE

          Tester Display Measurement Item/Range Normal Condition
          ACC PRESS SENS Accumulator pressure sensor / min 0 V, max 5 V Specified value 3 2 to 4 0 V
        2. Techstream

          ABS/VSC/TRAC: 

          ABS/VSC/TRAC REFERENCE

          Tester Display Measurement Item/Range Normal Condition
          Accumulator Pressure Sensor Accumulator pressure sensor / min 0 V, max 5 V 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.
    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 

      RESISTANCE SPECIFICATION

      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
      Fig 3: Identifying A18 Connector Terminals
      G04949615Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

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

    NG: REPLACE BRAKE FLUID RESERVOIR  (See REMOVAL )

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU AND BODY GROUND - BRAKE FLUID LEVEL WARNING SWITCH) 
    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.
      Fig 4: Identifying A19 And A18 Connector Terminals
      G04949616Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard resistance 

      RESISTANCE SPECIFICATION

      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.
    2. Disconnect the A18 switch connector
    3. Turn the power switch ON (IG)
    4. Measure the voltage according to the value(s) in the table below

      Standard voltage 

      VOLTAGE SPECIFICATION

      Tester Connection Switch Condition Specified Condition
      A18-2 - Body ground Power switch ON (IG) 8 to 14 V
      Fig 5: Identifying A18 Connector Terminals
      G04949617Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    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 power 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: USE SIMULATION METHOD TO CHECK  (See HOW TO PROCEED WITH TROUBLESHOOTING )

    A: REPLACE SKID CONTROL ECU  (See REMOVAL  )

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