ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1391/69

DTC Code DTC Name
C1391/69 Accumulator Leak Malfunction

DESCRIPTION

This DTC is stored if internal or external brake fluid leaks are detected due to improper sealing in the brake actuator (brake booster with master cylinder assembly) or brake booster pump assembly. Internal leaks are suspected if the pump motor operates frequently without braking.

DTC No. Detection Item INF Code DTC Detection Condition Trouble Area Note
C1391/69 Accumulator Leak Malfunction 351

Either of the following is detected:


  1. Accumulator pressure sensor input does not increase before braking or while the pump motor is operating.

  2. Accumulator pressure sensor input reduction rate exceeds the specification before braking and while the pump motor is not operating.

  • Brake fluid leaks

  • Brake actuator (Brake booster with master cylinder assembly)

    (Malfunctioning internal seal, low gas pressure in accumulator, etc.)

 Electronically controlled brake system DTC

CAUTION / NOTICE / HINT

Note

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

Click here

PROCEDURE


  1. CHECK FOR FLUID LEAK


    1. Check that there are no fluid leaks in the brake lines between the brake actuator (brake booster with master cylinder assembly) and the wheel cylinders.

    2. Check that the brakes are not dragging.

      OK
      There are no fluid leaks or dragging.
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE APPLICABLE PART

    OK

  2. RECONFIRM DTC


    1. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    2. Turn the power switch on (READY).

    3. Check if the same DTC is output.

      Click here


      Chassis > ABS/VSC/TRC > Trouble Codes
      Result
      Result Proceed to
      DTC C1391/69 is output. A
      DTC C1391/69 is not output. B

    B

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

    A

  3. PERFORM ACTIVE TEST USING GTS (SOLENOID VALVE)


    1. Turn the power switch off.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Active Test on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Active Test
      Tester Display Measurement Item Control Range Diagnostic Note
      ECB Solenoid (SMC/SRC/SCC) Switching solenoid valve (SMC/SRC/SCC) Solenoid ON/OFF

      • Operation sound of solenoid (clicking sound) can be heard

      • ECB: Electronically Controlled Brake System

      Chassis > ABS/VSC/TRC > Active Test
      Tester Display
      ECB Solenoid (SMC/SRC/SCC)

      Tech Tips

      The Active Test can be performed when the following conditions are met.


      • ABS main relay is on.

      • Park (P) is selected.

      • Parking brake is applied.

      • Vehicle speed is 0 km/h (0 mph).

    5. Perform the Active Test of the solenoid using the GTS.

    6. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Wheel Cylinder Pressure Sensor Wheel cylinder pressure sensor Min.: 0.00 V, Max.: 5.00 V Brake pedal released: 0.10 to 0.90 V Reading increases when brake pedal is depressed

      Chassis > ABS/VSC/TRC > Data List
      Tester Display
      Wheel Cylinder Pressure Sensor

    7. Check that the output value of the wheel cylinder pressure sensor does not increase.

      OK
      The output value of the wheel cylinder pressure sensor does not increase.

      Tech Tips

      If the output value increases, there may be brake fluid leaks in the brake actuator (brake booster with master cylinder assembly).

      Result
      Result Proceed to
      The output value of the wheel cylinder pressure sensor increases. A
      The output values of the wheel cylinder pressure sensor does not increase. B

    B

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for RHD: Click here

    A

  4. REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY


    1. Replace the brake actuator (brake booster with master cylinder assembly).

      for LHD: Click here

      for RHD: Click here

      Result
      Proceed to
      NEXT

    NEXT

    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for LHD: Click here
    REPLACE BRAKE BOOSTER PUMP ASSEMBLY for RHD: Click here