ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1202/68

DTC Code DTC Name
C1202/68 Master Reservoir Level Malfunction

DESCRIPTION

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

If a DTC for the fluid level drop is stored, the warning will be canceled and the DTC will be cleared when the fluid level returns to normal.

DTC No.

Detection Item

INF Code

DTC Detection Condition

Trouble Area

Note

C1202/68

Master Reservoir Level Malfunction

371

-

  • INF Code: 371

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

  • INF Code: -

    • The reservoir level remains low.

  • INF Code: 371

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

    • Open in wire harness

    • Skid control ECU (Brake booster with master cylinder assembly)

  • INF Code: -

    • Low brake fluid level

    • Brake fluid leaks

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

    • Short in wire harness

    • Brake disc rotor excessive wear

    • Skid control ECU (Brake booster with master cylinder assembly)

Electronically controlled brake system DTC

WIRING DIAGRAM

C269751E25

CAUTION / NOTICE / HINT

Note:

When replacing the skid control ECU (brake booster with master cylinder assembly), perform initialization and calibration of the linear solenoid valve.

Click here

Tip:

Before releasing the parking brake, chock the wheels for safety.

PROCEDURE

  1. CHECK BRAKE FLUID LEVEL

    1. Check that the brake fluid level is sufficient.

      OK

      Brake fluid level is sufficient.

      Tip:

      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 and brake booster with master cylinder assembly, and the brake booster with master cylinder assembly and wheel cylinders).

        Tip:

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

        Click here

      2. Check that the DTC is not output again.

        Click here

        Chassis > ABS/VSC/TRC > Trouble Codes

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

      Tip:

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

      1. Bleed the air from the brake system.

        Click here

      2. Connect the GTS to the DLC3.

      3. Turn the power switch on (IG).

      4. Select the Data List on the GTS.

        Click here

        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: 2.90 to 4.20 V

        When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

        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 0.55 V.

    Result

    Proceed to

    OK

    NG
    NG

    CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID

    OK

  2. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

    1. C213271C13

      *a

      Component without harness connected

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

      Turn the power switch off.

    2. Remove the reservoir filler cap.

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

    4. Disconnect the A9 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    5. 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

      Switch Condition

      Specified Condition

      1 (+) - 2 (E)

      Brake fluid level warning switch off (float up)

      1.84 to 2.16 kΩ

      1 (+) - 2 (E)

      Brake fluid level warning switch on (float down)

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

    for LHD:Click here

    for RHD:Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (BRAKE BOOSTER WITH MASTER CYLINDER 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 A110 skid control ECU (brake booster with master cylinder assembly) connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A110-36 (LBL) - A9-1 (+)

      Always

      Below 1 Ω

      A110-36 (LBL) or A9-1 (+) - Body ground

      Always

      10 kΩ or higher

      A9-2 (E) - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (SWITCH INPUT)

    1. C156573C22

      *a

      Front view of wire harness connector

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

      Reconnect the A110 skid control ECU (brake booster with master cylinder assembly) connector.

    2. Turn the power switch on (IG).

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

      Standard Voltage

      Tester Connection

      Switch Condition

      Specified Condition

      A9-1 (+) - Body ground

      Power switch on (IG)

      4 to 7 V

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

    for LHD:Click here

    for RHD:Click here

    OK

  5. CHECK BRAKE DISC

    1. Turn the power switch off.

    2. Reconnect the A9 brake fluid level warning switch (brake master cylinder reservoir assembly) connector.

    3. Disconnect the A105 brake pedal stroke sensor assembly connector.

    4. Perform a road test according to Freeze Frame Data or customer problem analysis. While driving, check for abnormal brake pedal vibration caused by brake discs that are worn or have excess runout.

      OK

      Brake pedal does not vibrate during braking.

      Tip:

      • An unevenly worn disc may vibrate the caliper pistons and cause fluctuations in brake line pressure, triggering a malfunction detection condition.

      • The brake pedal does not kick back due to caliper piston vibration during electronically controlled brake system control.

      • If the brake pedal stroke sensor assembly connector is disconnected, the fail-safe function will prohibit electronically controlled brake system control.

      • The Active Test does not prohibit electronically controlled brake system control when the vehicle is being driven, so disconnect the brake pedal stroke sensor assembly connector before continuing with inspection.

      • Uneven disc wear can be checked by measuring the disc thickness variation.

        for Front Brake:Click here

        for Rear Brake:Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE BRAKE DISC

    OK

  6. RECONFIRM DTC

    1. Reconnect the A105 brake pedal stroke sensor assembly connector.

    2. Clear the DTCs.

      Click here

      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the power switch on (READY).

    4. Perform a road test.

    5. Check if the same DTC is output.

      Click here

      Chassis > ABS/VSC/TRC > Trouble Codes

      Result

      Result

      Proceed to

      DTC C1202/68 is not output.

      A

      DTC C1202/68 is output.

      B
      Tip:

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step.

      Click here

    A

    USE SIMULATION METHOD TO CHECK

    Click hereClick hereClick here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY

    for LHD:Click here

    for RHD:Click here