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Home >> Lexus >> 2023 >> NX 250 AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (Electronically Controlled Brake System - Diagnostic Codes (4 Of 6)) >> Electronically Controlled Brake System (For Hev Model) >> Dtc C139A-00: Brake Pressure Control Solenoid Circuit Malfunction; Dtc C13D9-00: Brake Pressure Too Low (Brake Booster); Dtc C14Ec-7E: Brake Pressure Control Solenoid "C" Actuator Stuck On [11/2021 - ] >> Procedure

Dtc C139A-00: Brake Pressure Control Solenoid Circuit Malfunction; Dtc C13D9-00: Brake Pressure Too Low (Brake Booster); Dtc C14Ec-7E: Brake Pressure Control Solenoid "C" Actuator Stuck On [11/2021 - ]: Procedure

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  1. Customer Problem Analysis (Check Condition When Malfunction Occurred) And Freeze Frame Data 
    1. Interview The Customer To Check The Vehicle Conditions When The Brake System Warning Light (Yellow Indicator) Illuminated.
    2. Using The Gts, Check For Freeze Frame Data That Is Recorded When A Dtc Is Stored.

      Refer To Freeze Frame Data [11/2021 - ]

      Chassis > Brake Booster > Trouble Codes 

      Hint: 

      Freeze Frame Data Is Only Stored Once When A Dtc Is Stored.

      Result

      Proceed To
      Next

    Result: 

    Next 

    See Step  2

  2. Clear Dtc 
    1. Clear The DTCS.

      Chassis > Brake Booster > Clear DTCS 

      Chassis > Brake/Epb > Clear DTCS 

    2. Turn The Ignition Switch Off.

      Result

      Proceed To
      Next

    Result: 

    Next 

    See Step  3

  3. Check Dtc 
    1. Based On The Freeze Frame Data And Interview With The Customer, Attempt To Reproduce The Conditions When The Malfunction Occurred.
    2. Check If The Same Dtc Is Output.

      Chassis > Brake Booster > Trouble Codes 

      Chassis > Brake/Epb > Trouble Codes 

      Result

      Result Proceed To
      Only DTCS C139A-00, C13D9-00 And/Or C14Ec-7E Are Output. A
      DTCS Other Than C139A-00, C13D9-00 And/Or C14Ec-7E Are Output. B

    Result: 

    B 

    Repair Circuits Indicated By Output DTCS 

    Result: 

    A 

    See Step  4

  4. Check For Fluid Leak 
    1. Based On The Freeze Frame Data Or Interview With The Customer, Inspect The Following Items For Brake Fluid Leaks:
      • The Brake Lines From The Brake Booster With Master Cylinder Assembly To Each Wheel Cylinder.
      • The Main Body Of The Brake Booster With Master Cylinder Assembly And Brake Actuator Assembly.

      Ok

      There Are No Fluid Leaks.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Applicable Part 

    Result: 

    Ok 

    See Step  5

  5. Perform Air Bleeding 
    1. Clear The DTCS.

      Chassis > Brake Booster > Clear DTCS 

      Chassis > Brake/Epb > Clear DTCS 

    2. Perform The Air Bleeding Procedure In Bleed Brake System.

      Refer To Bleeding [11/2021 - ]

      Result

      Proceed To
      Next

    Result: 

    Next 

    See Step  6

  6. Check Brake Booster With Master Cylinder Assembly (Actuator Side) 
    1. Turn The Ignition Switch Off.
    2. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connectors.

      Ok

      The Connector Is Securely Connected.

    3. Disconnect The A39 No. 1 Skid Control ECU (Brake Booster With Master Cylinder Assembly) Connector.
    4. Check Both The Connector Case And The Terminals For Deformation And Corrosion.

      Ok

      No Deformation Or Corrosion.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Replace Brake Booster With Master Cylinder Assembly. Refer To  Removal [11/2021 - ] 

    Result: 

    Ok 

    See Step  7

  7. Check Harness And Connector (Vehicle Side) 
    1. Reconnect The A39 No. 1 Skid Control ECU (Brake Booster With Master Cylinder Assembly) Connector.
    2. Measure The Voltage And Resistance On The Wire Harness Side.

      Refer To Terminals Of ECU [11/2021 - ]

      Ok

      Voltage And Resistance Readings Are All Normal.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ok 

    See Step  8

  8. Clear Dtc 
    1. Clear The DTCS.

      Chassis > Brake Booster > Clear DTCS 

      Chassis > Brake/Epb > Clear DTCS 

    2. Turn The Ignition Switch Off.

      Result

      Proceed To
      Next

    Result: 

    Next 

    See Step  9

  9. Reconfirm Dtc 
    1. Based On The Freeze Frame Data And Interview With The Customer, Attempt To Reproduce The Conditions When The Malfunction Occurred.
    2. Check If The Same Dtc Is Output.

      Chassis > Brake Booster > Trouble Codes 

      Chassis > Brake/Epb > Trouble Codes 

      Hint: 

      If The System Returns To Normal, It Is Suspected That A Dtc Was Stored Due To A Poor Connection Of A Terminal In A Connector, Air In The System, Etc.

      Result

      Result Proceed To
      DTCS C139A-00, C13D9-00 And C14Ec-7E Are Not Output. A
      DTCS C139A-00, C13D9-00 And/Or C14Ec-7E Are Output. B
      Dtc C139A-00 And C140A-00 Are Output At The Same Time. C

    Result: 

    A 

    Use Simulation Method To Check. Refer To  How To Proceed With Troubleshooting [11/2021 - ] 

    Result: 

    B 

    Replace Brake Booster With Master Cylinder Assembly. Refer To  Removal [11/2021 - ] 

    Result: 

    C 

    Replace Brake Booster With Master Cylinder Assembly And Brake Actuator Assembly 

    For Brake Booster With Master Cylinder Assembly: Refer To Removal [11/2021 - ]

    For Brake Actuator Assembly: Refer To Removal [11/2021 - ]

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