ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1391/69

DTC Code DTC Name
C1391/69 Accumulator Leak Malfunction

DESCRIPTION

The DTC is stored if an internal or external brake fluid leak is detected due to improper sealing in the brake actuator assembly. Internal leakage is suspected if the pump motor operates frequently without braking.

DTC Code INF Code DTC Detection Condition Trouble Area
C1391/69 591

Either of the following is detected:


  1. Before braking and when the pump motor is running, the accumulator pressure sensor input does not rise.

  2. Before braking and when the pump motor is not running, the accumulator pressure sensor input continues to fall at a greater rate than the standard value.

  • Brake fluid leak

  • Brake actuator assembly

  • Skid control ECU assembly

CAUTION / NOTICE / HINT

Note

When replacing the skid control ECU assembly or brake actuator assembly, perform initialization and calibration of the linear solenoid valve Click here.

PROCEDURE


  1. CHECK FOR FLUID LEAK


    1. Check that there is no fluid leakage in the brake line between the brake actuator assembly and the wheel cylinder which is indicated by DTCs.

    2. Check that the brake is not dragging.

      OK
      There is no fluid leakage or dragging.

    NG

    REPAIR OR REPLACE APPLICABLE PART

    OK

  2. PERFORM ACTIVE TEST USING GTS (ACCUMULATOR PRESSURE SENSOR)


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    3. Select the Data List on the GTS Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Accumulator Sensor Accumulator pressure sensor / Min.: 0.00 V, Max.: 5.00 V Specified value: 2.6 to 3.8 V When brake fluid is stored in the accumulator: Accumulator pressure changes in accordance with volume of fluid stored in the accumulator

    4. Wait a few minutes without operating the brake pedal.

    5. Check that the output value of the accumulator pressure sensor does not decrease and that the pump motor is not activated due to a decrease in accumulator pressure.

      OK
      Accumulator pressure does not decrease and the pump motor is not activated due to a decrease in accumulator pressure.

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    OK

  3. RECONFIRM DTC


    1. Clear the DTCs Click here.

    2. Turn the power switch on (READY).

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

      Result
      Result Proceed to
      DTC (C1391/69) is output A
      DTC (C1391/69) is not output B

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here

    B

    REPLACE SKID CONTROL ECU ASSEMBLY Click here