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 or brake booster pump. 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 booster pump

  • Brake actuator assembly

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. CHECK FOR FLUID LEAK


    1. A01NHA8

      Check that there is no fluid leakage in the brake line between the brake actuator 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. 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

    B

    REPLACE BRAKE ACTUATOR ASSEMBLY Click here

    A

  3. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (SOLENOID VALVE)


    1. Turn the power switch off.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the power switch on (IG).

    4. Select the Active Test on the intelligent tester Click here.

      Tech Tips

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


      • ABS main relays 1 and 2 are on.

      • Shift lever is in P.

      • Parking brake is applied.

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

      ABS/VSC/TRC
      Tester Display Test Part Control Range Diagnostic Note
      ECB* Solenoid (SMC1) Master cut solenoid (SMC1) Solenoid ON/OFF Operation sound of solenoid (clicking sound) can be heard
      ECB* Solenoid (SMC2) Master cut solenoid (SMC2) Solenoid ON/OFF Operation sound of solenoid (clicking sound) can be heard
      ECB* Solenoid (SLRRL) Value Close Linear solenoid (RLR) valve Valve close ON/OFF Operation sound of solenoid (clicking sound) can be heard
      ECB* Solenoid (SLRRR) Value Close Linear solenoid (RRR) valve Valve close ON/OFF Operation sound of solenoid (clicking sound) can be heard

      *: Electronically Controlled Brake System

    5. Perform the Active Test of the solenoid using the intelligent tester.

      A01NF5ME02

    6. Select the Data List on the intelligent tester Click here.

      ABS/VSC/TRC
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      FR W/C Sensor FR wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V When brake pedal is released: 0.3 to 0.7 V Reading increases when brake pedal is depressed
      FL W/C Sensor FL wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V When brake pedal is released: 0.3 to 0.7 V Reading increases when brake pedal is depressed
      RR W/C Sensor RR wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V When brake pedal is released: 0.3 to 0.7 V Reading increases when brake pedal is depressed
      RL W/C Sensor RL wheel cylinder pressure sensor / Min.: 0 V, Max.: 5 V When brake pedal is released: 0.3 to 0.7 V Reading increases when brake pedal is depressed

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

      OK
      The output value of each wheel cylinder does not increase.

      Tech Tips

      If any output value increases, there may be a brake fluid leak in the brake actuator.

      Result
      Result Proceed to
      The output value of any wheel cylinder increases A
      The output values of all wheel cylinders do not increase B

    B

    REPLACE BRAKE BOOSTER PUMP Click here

    A

    REPLACE BRAKE ACTUATOR AND BRAKE BOOSTER PUMP ASSEMBLY Click here