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Home >> Toyota >> 2024 >> Corolla LE >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 70 (Electronically Controlled Brake System (HEV) - Diagnostic Codes (2 Of 6)) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> DTC C1202: Master Reservoir Level Malfunction [01/2019 - 09/2022] >> Procedure

DTC C1202: Master Reservoir Level Malfunction [01/2019 - 09/2022]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. CHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch off.
    3. Turn the power switch on (IG).
    4. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTC C1202 is output. A
      DTC C120F is output with DTC C1202. B

    Result: 

    B 

    GO TO DTC (C120F). Refer to  DTC C120F: Open in Master Reservoir Level Switch Circuit [01/2019 - 09/2022] 

    Result: 

    A 

    See step  2

  2. CHECK BRAKE FLUID LEVEL 
    1. Check that the brake fluid level is sufficient.

      HINT: 

      If the fluid level is low, check for fluid leaks, and repair as necessary.

      1. Check for brake fluid leaks (connection between the brake booster pump assembly, brake master cylinder reservoir assembly (brake booster with master cylinder assembly), brake booster with master cylinder assembly, and wheel cylinders).

        HINT: 

        If no leaks exist, add and adjust fluid using the Techstream.

        Refer to ON-VEHICLE INSPECTION [01/2019 - 09/2022]

      2. Check the thickness of the brake pad lining.

        for Front Brake: Refer to INSPECTION [01/2019 - 09/2022]

        for Rear Brake: Refer to INSPECTION [06/2018 - 09/2022]

        HINT: 

        If the thickness is less than the standard, replace the brake pads with new ones.

    2. Check that there are no leaks from the connections between the brake booster pump assembly and brake booster with master cylinder assembly.

      HINT: 

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

      1. Bleed the air from the brake system.

        Refer to BLEEDING [01/2019 - 09/2022]

      2. Turn the power switch off.
      3. Disconnect the A9 brake pedal stroke sensor assembly connector.
      4. Select the Data List on the Techstream.

        Refer to DATA LIST / ACTIVE TEST [01/2019 - 09/2022]

        Chassis > ABS/VSC/TRAC > Data List 

        Tester Display Measurement Item Range Normal Condition Diagnostic Note
        MT Voltage Value MT voltage value Min.: 0.00 V, Max.: 20.00 V Pump motor off: 0.00 V
        Pump motor on: 12.00 V        		 -
        Accumulator Pressure Accumulator pressure output value Min.: 0.00 MPa, Max.: 24.48 MPa 15.00 to 21.00 MPa
        (Pressure stable and pump motor stopped)        		 When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

        Chassis > ABS/VSC/TRAC > Data List 

        Tester Display
        MT Voltage Value
        Accumulator Pressure
      5. Depress the brake pedal several times to operate the pump motor, then wait until it stops.
      6. After the pump motor stops, wait for 30 seconds, then check the drop in the accumulator pressure sensor output value and the state of the pump motor.

      Result

      Result Proceed to
      The drop in the accumulator pressure sensor output value is less than 2.50 MPa 30 seconds after the pump motor stops, and the pump motor does not operate within 30 seconds after the pump motor stops. A
      The drop in the accumulator pressure sensor output value is 2.50 MPa or more 30 seconds after the pump motor stops, or the pump motor operates within 30 seconds after the pump motor stops. B

    Result: 

    B 

    CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID 

    Result: 

    A 

    See step  3

  3. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH) 
    1. Turn the power switch off.
      GTY562748Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without harness connected
      (Brake Fluid Level Warning Switch (Brake Booster with Master Cylinder Assembly))
    2. Reconnect the A9 brake pedal stroke sensor assembly connector.
    3. Remove the brake master cylinder reservoir filler cap assembly.
    4. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

    5. Disconnect the A52 brake fluid level warning switch (brake booster with master cylinder assembly) connector.
    6. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    7. Measure the resistance according to the value(s) in the table below.

      HINT: 

      A float is located inside the brake master cylinder reservoir assembly (brake booster with master cylinder assembly). Its position changes according to the level of brake fluid.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2 (LBL) - 1 (GND) Brake fluid level warning switch (brake booster with master cylinder assembly) off (float up) 1.84 to 2.16 kΩ
      2 (LBL) - 1 (GND) Brake fluid level warning switch (brake booster with master cylinder assembly) on (float down) Below 1 Ω
      (Brake fluid level is low)
    8. If there are no problems after completing the preceding inspection, adjust the brake fluid to the MAX level with the power switch on (IG).

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [01/2019 - 09/2022] 

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY - BRAKE FLUID LEVEL WARNING SWITCH (BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY)) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

      OK

      The connector is securely connected.

    2. Disconnect the A48 skid control ECU (brake booster with master cylinder assembly) connector.
    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A48-16 (LBL) - A52-2 (LBL) Always Below 1 Ω
      A48-16 (LBL) or A52-2 (LBL) - Body ground Always 10 kΩ or higher
      A52-1 (GND) - Body ground 1 minute or more after disconnecting the cable from the negative (-) auxiliary battery terminal Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SWITCH INPUT) 
    1. Reconnect the A48 skid control ECU (brake booster with master cylinder assembly) connector.
      GTY921786Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Brake Fluid Level Warning Switch (Brake Booster with Master Cylinder Assembly))
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A52-2 (LBL) - Body ground Power switch on (IG) 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [01/2019 - 09/2022] 

    Result: 

    OK 

    See step  6

  6. RECONFIRM DTC 
    1. Turn the power switch off.
    2. Reconnect the A52 brake fluid level warning switch (brake booster with master cylinder assembly) connector.
    3. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    4. Turn the power switch off.
    5. Turn the power switch on (READY).
    6. Perform a road test.
    7. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTC C1202 is not output. A
      DTC C1202 is output. B

    Result: 

    A 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

    Result: 

    B 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [01/2019 - 09/2022] 

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