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 master cylinder reservoir is detected, the signal is input to the skid control ECU.

If the DTC for the fluid level drop is memorized, the warning will be canceled and the DTC will not be stored when the fluid level returns to normal.

DTC Code INF Code DTC Detection Condition Trouble Area
C1202/68 371 An open is detected in the switch signal circuit for 2 seconds or more.

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

  • Open in wire harness

  • Brake booster with master cylinder (Skid control ECU)
↑ - The reservoir level remains low.

  • Low brake fluid level

  • Brake fluid leaks

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

  • Short in wire harness

  • Brake disc rotor excessive wear

  • Brake booster with master cylinder (Skid control ECU)

WIRING DIAGRAM

B001KYVE35

CAUTION / NOTICE / HINT

Note

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

Tech Tips

When 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.

      Tech Tips

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

        Tech Tips

        If no leaks exist, add and adjust fluid using the intelligent tester Click here.

      2. Check that the trouble code is not output again Click here.

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

      Tech Tips

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


      1. Bleed the air from the brake systems Click here.

      2. Connect the intelligent tester to the DLC3.

      3. Turn the power switch on (IG).

      4. Select the Data List on the intelligent tester Click here.

        ABS/VSC/TRC
        Tester Display Measurement Item/Range Normal Condition Diagnostic Note
        Accumulator Sensor Accumulator pressure sensor / Min.: 0 V, Max.: 5 V Specified value: 2.9 to 4.2 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

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

      6. Check that the accumulator pressure sensor output values change is within the specified range.

        OK
        Accumulator pressure sensor output values change is within 0.55 V.

    NG

    CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID

    OK

  2. INSPECT BRAKE FLUID LEVEL WARNING SWITCH


    1. B001LINE02
      Text in Illustration
      *a

      Component without harness connected

      (Brake Fluid Level Warning Switch)

      Turn the power switch off.

    2. Remove the reservoir filler cap and strainer.

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

    4. Disconnect the brake fluid level warning switch connector.

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

      Tech Tips

      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
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE MASTER CYLINDER RESERVOIR (BRAKE FLUID LEVEL WARNING SWITCH) Click here

    C

    REPLACE BRAKE MASTER CYLINDER RESERVOIR (BRAKE FLUID LEVEL WARNING SWITCH) Click here

    A

  3. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE FLUID LEVEL WARNING SWITCH)


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

    2. Disconnect the skid control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A61-36 (LBL) - A31-1 (+) Always Below 1 Ω
      A61-36 (LBL) - Body ground Always 10 kΩ or higher
      A31-2 (E) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT SKID CONTROL ECU (SWITCH INPUT)


    1. B001LI9E01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Brake Fluid Level Warning Switch)

      Reconnect the skid control ECU 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
      A31-1 (+) - Body ground Power switch on (IG) 11 to 14 V
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    A

  5. CHECK BRAKE DISC


    1. Turn the power switch off.

    2. Reconnect the brake fluid level warning switch connector.

    3. Disconnect the brake pedal stroke sensor connector.

    4. Perform a road test according to Freeze Frame Data or customer problem analysis. Check the brake line pressure vibration caused due to uneven wear of the disc according to brake pedal vibration.

      OK
      Brake pedal does not vibrate during braking.

      Tech Tips


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

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

      • If the brake pedal stroke sensor 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 driving the vehicle, so disconnect the stroke sensor connector before continuing with inspection.

      • Disc uneven wear can be checked by measuring the disc thickness variation (See page for front, or Click here for rear).


    NG

    REPLACE BRAKE DISC

    OK

  6. RECONFIRM DTC


    1. Reconnect the brake pedal stroke sensor connector.

    2. Clear the DTCs Click here.

    3. Turn the power switch on (READY).

    4. Perform a road test.

    5. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTC (C1202/68) is not output A
      DTC (C1202/68) is output (for LHD) B
      DTC (C1202/68) is output (for RHD) C

      Tech Tips

      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

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here

    C

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Click here