ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1391/69

DTC Code DTC Name
C1391/69 Accumulator Leak Malfunction

DESCRIPTION

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

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

When 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 falling rate of the accumulator pressure sensor input continues to be greater than the standard value.

  • Brake fluid leakage (Connection between brake accumulator pump and brake actuator, or brake actuator and wheel cylinder)

  • Brake accumulator pump

  • Brake actuator

INSPECTION PROCEDURE

Note

When replacing the brake actuator, perform initialization of the linear solenoid valve and calibration Click here.

PROCEDURE


  1. CHECK BRAKE FLUID LEAKAGE


    1. A01H20SE01

      Check that there is no fluid leakage in the brake line between the brake actuator and the wheel cylinder which is the cause of 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. CHECK DTC


    1. Clear the DTC Click here.

    2. Turn the power switch OFF.

    3. Turn the power switch ON (READY).

    4. Check if the same DTC C1391 is recorded.

      Result
      Result Proceed to
      DTC C1391 is output A
      DTC C1391 is not output for LHD B
      for RHD C

    B

    REPLACE BRAKE ACCUMULATOR PUMP Click here

    C

    REPLACE BRAKE ACCUMULATOR PUMP Click here

    A

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SMC1, SMC2, SLRRR, AND SLRRL)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the power switch ON (IG).

    3. Turn the intelligent tester main switch on.

    4. Select the ACTIVE TEST mode on the intelligent tester.

      Tech Tips

      The ACTIVE TEST can be performed when the following conditions are met.


      • Main relay 1 and 2 are on.

      • Shift lever is P position.

      • Parking brake is on.

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

      ABS/VSC/TRAC:
      Tester Display Test Part Control Range Diagnostic Note
      Electronically Controlled Brake System Solenoid (SMC1) Turns electronically controlled brake system solenoid (SMC1) ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SMC2) Turns electronically controlled brake system solenoid (SMC2) ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SLRRR) Valve Close Turns SLRRR solenoid ON / OFF Operation sound of solenoid (clicking sound) can be heard
      Electronically Controlled Brake System Solenoid (SLRRL) Valve Close Turns SLRRL solenoid ON / OFF Operation sound of solenoid (clicking sound) can be heard

    5. Using the intelligent tester, turn SMC1, SMC2, SLRRR, or SLRRL ON.

      A01GXB1E02

    6. Check that each wheel cylinder's output value does not increase.

      OK
      Each wheel cylinder's output value does not increase.

      Tech Tips

      If any of wheel cylinder's output value increases, there may be a brake fluid leak in the brake actuator.

      Result
      Result Proceed to
      Any of wheel cylinder's output value increases. for LHD

      A and C*

      for RHD

      B and D*

      Each wheel cylinder's output value does not increase. for LHD C
      for RHD D

      Tech Tips

      *: Replace the brake actuator and brake accumulator pump.


    B

    REPLACE BRAKE ACTUATOR Click here

    C

    REPLACE BRAKE ACCUMULATOR PUMP Click here

    D

    REPLACE BRAKE ACCUMULATOR PUMP Click here

    A

    REPLACE BRAKE ACTUATOR Click here