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ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1202

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DTC Code DTC Name
C1202 Master Reservoir Level Malfunction
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DESCRIPTION

When a fluid level drop in the brake master cylinder reservoir assembly is detected, a signal is sent to the skid control ECU assembly.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1202 Master Reservoir Level Malfunction

511

512

  • INF Code: 511


    • Pump motor operates for specified period when reservoir level drops.

  • INF Code: 512


    • An open is detected in the switch signal circuit for 2 seconds or more.

  • INF Code: 511


    • Low brake fluid level

    • Brake fluid leaks

    • Brake fluid level warning switch (Brake master cylinder reservoir assembly) internal short circuit

    • Short in wire harness

    • Skid control ECU assembly

  • INF Code: 512


    • Brake fluid level warning switch (Brake master cylinder reservoir assembly) internal open circuit

    • Open in wire harness

    • Skid control ECU assembly

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Table 1. *a Brake Fluid Level Warning Switch (Brake Master Cylinder Reservoir Assembly) *b Skid Control ECU Assembly
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

When replacing the skid control ECU assembly, perform initialization and calibration of the linear solenoid valve.

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PROCEDURE


  1. Click here

    CHECK BRAKE FLUID LEVEL


    1. Check that the brake fluid level is sufficient.

      Tip:

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

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

      • If no leaks exist, add and adjust fluid and then check that the trouble code is not output again.

      OK
      Brake fluid level is sufficient.

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

      Tip:

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


      1. Bleed air from the brake actuator assembly.

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      2. Connect the GTS to the DLC3.

      3. Turn the power switch on (IG).

      4. Select the Data List on the GTS.

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        1. Chassis > ABS/VSC/TRC > Data List
          Tester Display Measurement Item Range Normal Condition Diagnostic Note
          Accumulator Sensor Accumulator pressure sensor Min.: 0.00 V, Max.: 5.00 V Specified value: 2.60 to 3.80 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator



        1. Chassis > ABS/VSC/TRC > Data List
          Tester Display
          Accumulator Sensor




      5. Depress the brake pedal 4 or 5 times to operate the pump motor.

      6. Wait for 30 seconds without depressing the brake pedal.

      7. Check that the accumulator pressure sensor output value change is within the specified range.

        OK
        Accumulator pressure sensor output value change is less than 0.20 V.
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID

  2. Click here

    INSPECT BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY


    1. B004X9MC03
      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch (Brake Master Cylinder Reservoir Assembly))

      Remove the brake master cylinder reservoir filler cap and strainer.

    2. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    3. Disconnect the A19 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

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

      Tip:

      A float is located inside the reservoir. Its position changes according to the level of brake fluid.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A19-2 (LBL) - A19-1 (GND) Brake fluid level warning switch (Brake master cylinder reservoir assembly) off (float up) 1.84 to 2.16 kΩ
      A19-2 (LBL) - A19-1 (GND) Brake fluid level warning switch (Brake master cylinder reservoir assembly) on (float down) Below 1 Ω
      Tip:

      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

    • OKClick here
    • NG

      REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY for LHD:Click here

      REPLACE BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY for RHD:Click here

  3. Click here

    CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU ASSEMBLY - BRAKE MASTER CYLINDER RESERVOIR ASSEMBLY)


    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.

    2. Disconnect the A11 skid control ECU assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A11-6 (LBL) - A19-2 (LBL) Always Below 1 Ω
      A11-6 (LBL) or A19-2 (LBL) - Body ground Always 10 kΩ or higher
      A19-1 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    • OKClick here
    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR

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    INSPECT SKID CONTROL ECU ASSEMBLY (SWITCH INPUT)


    1. B004T34C02
      *a

      Component with harness connected

      (Skid Control ECU Assembly)

      Reconnect the A11 skid control ECU assembly connector.

    2. Reconnect the A19 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    3. Turn the power switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A11-6 (LBL) - Body ground Brake fluid level warning switch (Brake master cylinder reservoir assembly) off → on 4 to 8 V → Below 1.5 V
      Result
      Proceed to
      OK
      NG

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    RECONFIRM DTC


    1. Clear the DTCs.

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      1. Chassis > ABS/VSC/TRC > Clear DTCs


    2. Turn the power switch off.

    3. Turn the power switch on (IG).

    4. Check if the same DTC is output.

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      1. Chassis > ABS/VSC/TRC > Trouble Codes


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

    • A

      USE SIMULATION METHOD TO CHECKClick here

    • B

      REPLACE SKID CONTROL ECU ASSEMBLY for LHD:Click here

      REPLACE SKID CONTROL ECU ASSEMBLY for RHD:Click here