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 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 591

Either of the following is detected:


  1. Accumulator pressure sensor input does not increase before braking and 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 assembly

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

  • Skid control ECU assembly

 Electronically controlled brake system DTC

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 are no fluid leaks in the brake lines between the brake actuator 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. READ VALUE USING GTS (ACCUMULATOR PRESSURE SENSOR)


    1. Turn the power switch off.

    2. Connect the GTS to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Data List on the GTS.

      Click here


      Chassis > ABS/VSC/TRC > Data List
      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Accumulator Sensor Accumulator pressure sensor Min.: 0.00 V, Max.: 5.00 V Specified value: 2.60 to 3.80 V 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
      Accumulator Sensor

    5. Depress the brake pedal 4 or 5 times and operate the pump motor.

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

    7. 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.
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE BRAKE ACTUATOR ASSEMBLY for LHD: Click here
    REPLACE BRAKE ACTUATOR ASSEMBLY for RHD: Click here

    OK

  3. RECONFIRM DTC


    1. Turn the power switch off.

    2. Clear the DTCs.

      Click here


      Chassis > ABS/VSC/TRC > Clear DTCs

    3. Turn the power switch off.

    4. Turn the power switch on (READY).

    5. Check if the same DTC is output.

      Click here


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

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE SKID CONTROL ECU ASSEMBLY for LHD: Click here
    REPLACE SKID CONTROL ECU ASSEMBLY for RHD: Click here