ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1202

DTC Code DTC Name
C1202 Master Reservoir Level Malfunction

DESCRIPTION

If the skid control ECU (brake booster with master cylinder assembly) detects that the brake fluid level is low or there is an open in the brake fluid level warning switch signal circuit, DTC C1202 is stored.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1202 Master Reservoir Level Malfunction 1126

Either of the following is detected:


  1. The brake fluid level warning switch signal circuit is open for a certain period of time.

  2. The reservoir level is low for a certain period of time.

  • Open or short in brake fluid level warning switch (brake booster with master cylinder assembly)

  • Brake fluid leaks

  • Open or short in wire harness

  • Low brake fluid

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

Electronically controlled brake system DTC

Tech Tips

The DTC is cleared when the conditions return to normal.
DTC Detection Conditions: C1202 INF Code: 1126
Vehicle Condition
Pattern 1 Pattern 2
Diagnosis Condition - - -
Malfunction Status The brake fluid level warning switch signal circuit is open for a certain period of time. ○ -
The reservoir level is low for a certain period of time. - ○
Detection Time - -
Number of Trips 1 trip 1 trip

Tech Tips

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

B004Q96E02
*a Brake Fluid Level Warning Switch (Brake Booster with Master Cylinder Assembly)
*b Skid Control ECU (Brake Booster with Master Cylinder Assembly)

CAUTION / NOTICE / HINT

Note

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

Click here

PROCEDURE


  1. CLEAR DTC


    1. Clear the DTCs.


      Chassis > ABS/VSC/TRC > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK DTC


    1. Turn the power switch off.

    2. Turn the power switch on (IG).

    3. Check if the same DTC is output.


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      Only C1202 is output A
      Other than above B

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    A

  3. CHECK BRAKE FLUID LEVEL


    1. Check that the 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 assembly, brake master cylinder reservoir assembly (brake booster with master cylinder assembly), brake booster with master cylinder assembly, and wheel cylinders).

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

        Click here

      2. Check the thickness of the brake pad lining.

        for Front Brake: Click here

        for Rear Brake: Click here

        Tech Tips

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

      Result
      Proceed to
      NEXT

    NEXT

  4. CHECK FOR FLUID LEAK


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

      Tech Tips

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


      1. Bleed the air from the brake system.

        Tech Tips

        Click here

      2. Turn the power switch off.

      3. Disconnect the A45 brake pedal stroke sensor assembly connector.

      4. Select the Data List on the GTS.


        Chassis > ABS/VSC/TRC > 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/TRC > 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
      30 seconds after the pump motor stops the drop in the value of Accumulator Pressure after the pump motor stops is less than 2.50 MPa and pump motor does not operate within 30 seconds A
      30 seconds after the pump motor stops the drop in the value of Accumulator Pressure is 2.50 MPa or more or pump motor operates within 30 seconds B

    B

    CHECK AND REPAIR BRAKE FLUID LEAKS OR ADD FLUID

    A

  5. INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY (BRAKE FLUID LEVEL WARNING SWITCH)


    1. Turn the power switch off.

    2. Reconnect the A45 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 A44 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.

      Tech Tips

      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
      A44-2 (LBL) - A44-1 (GND) Brake fluid level warning switch (brake booster with master cylinder assembly) off (float up) 1.84 to 2.16 kΩ
      A44-2 (LBL) - A44-1 (GND) Brake fluid level warning switch (brake booster with master cylinder assembly) on (float down) Below 1 Ω

      Tech Tips

      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

    NG

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    OK

  6. 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 A41 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
      A41-16 (LBL) - A44-2 (LBL) Always Below 1 Ω
      A41-16 (LBL) or A44-2 (LBL) - Body ground Always 10 kΩ or higher
      A44-1 (GND) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. B004Q2TC16
      *a

      Front view of wire harness connector

      (to Brake Fluid Level Warning Switch (Brake Booster with Master Cylinder Assembly))

      Reconnect the A41 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 Condition Specified Condition
      A44-2 (LBL) - Body ground Power switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here

    OK

  8. CLEAR DTC


    1. Turn the power switch off.

    2. Reconnect the A44 brake fluid level warning switch (brake booster with master cylinder assembly) connector.

    3. Clear the DTCs.


      Chassis > ABS/VSC/TRC > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  9. RECONFIRM DTC


    1. Turn the power switch off.

    2. Turn the power switch on (READY).

    3. Perform a road test.

    4. Check if the same DTC is output.


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      C1202 is not output A
      C1202 is output B

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY for RHD: Click here