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 off.

    3. Turn the power switch on (READY).

    4. 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

    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)
      Tip:

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

      • ABS main relay is on.

      • Shift lever is in P.

      • 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.

      Tip:

      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

    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

    Click here