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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 C12F8-12: Ecb Solenoid Control "A" Circuit Short To Battery; Dtc C12F8-14: Ecb Solenoid Control "A" Circuit Short To Ground Or Open [11/2021 - ] >> Procedure

Dtc C12F8-12: Ecb Solenoid Control "A" Circuit Short To Battery; Dtc C12F8-14: Ecb Solenoid Control "A" Circuit Short To Ground Or Open [11/2021 - ]: Procedure

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  1. Read Value Using Gts (Bs Voltage) 
    1. Perform The Active Test And Operate The Main Relay.
    2. Monitor The Value Of Bs Voltage When The Active Test Is Being Performed.

      Chassis > Brake Booster > Active Test 

      Tester Display Measurement Item Control Range Restrict Condition Diagnostic Note
      Ecb Main Relay Main Relay Off / On Vehicle Condition: Vehicle Stopped
      Hint: 
      To Protect This Actuator And Solenoid, This Test Will Only Last 5 Seconds.      		 Ecb: Electronically Controlled Brake System

      Chassis > Brake Booster > Data List 

      Tester Display Measurement Item Range Normal Condition Diagnostic Note
      Bs Voltage Bs Voltage Value Min.: 0.0 V
      Max.: 25.5 V      		 - Changes In Proportion To Auxiliary Battery Voltage

      Chassis > Brake Booster > Active Test 

      Active Test Display
      Ecb Main Relay
      Data List Display
      Bs Voltage

      Hint: 

      During The Active Test, The Voltage Indicated By Bs Voltage Changes In Proportion To The Voltage Of The Auxiliary Battery.

      Result

      Result Proceed To
      During The Active Test, The Voltage Indicated By Bs Voltage Increases To The Approximate Voltage Of The Auxiliary Battery. A
      During The Active Test, The Voltage Indicated By Bs Voltage Remains Low Around 0 V. (W/O Advanced Park (Remote Controlled)) B
      During The Active Test, The Voltage Indicated By Bs Voltage Remains Low Around 0 V. (W/ Advanced Park (Remote Controlled)) C

    Result: 

    B 

    See Step  4

    Result: 

    C 

    See Step  6

    Result: 

    A 

    See Step  2

  2. Clear Dtc 
    1. Clear The DTCS.

      Chassis > Brake Booster > Clear DTCS 

    2. Turn The Ignition Switch Off.

      Result

      Proceed To
      Next

    Result: 

    Next 

    See Step  3

  3. 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 

      Result

      Result Proceed To
      DTCS C12F8-12 And C12F8-14 Are Not Output. A
      DTCS C12F8-12 And/Or C12F8-14 Are Output. B

    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 - ] 

  4. Check Harness And Connector (+Bi1 Terminal) 
    1. Turn The Ignition Switch Off.
    2. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.

      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.

    5. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-14 (+Bi1) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ok 

    See Step  5

  5. Check Harness And Connector (Bs Terminal) 
    1. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-15 (Bs) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

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

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

  6. Check Harness And Connector (+Bi1 Terminal) 
    1. Turn The Ignition Switch Off.
    2. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.

      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.

    5. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-14 (+Bi1) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    See Step  11

    Result: 

    Ok 

    See Step  7

  7. Check Harness And Connector (Bs Terminal) 
    1. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-15 (Bs) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

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

    Result: 

    Ng 

    See Step  8

  8. Check Harness And Connector (B1A1 Terminal) 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The G133 Second Power Supply Remote Parking Circuit Connector.
    3. Check Both The Connector Case And The Terminals For Deformation And Corrosion.

      Ok

      No Deformation Or Corrosion.

    4. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G133-2 (B1A1) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ok 

    See Step  9

  9. Check Harness And Connector (Second Power Supply Remote Parking Circuit - Brake Booster With Master Cylinder Assembly And Gnd Terminal) 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The G132 And G134 Second Power Supply Remote Parking Circuit Connectors.
    3. Check Both The Connector Case And The Terminals For Deformation And Corrosion.

      Ok

      No Deformation Or Corrosion.

    4. Measure The Resistance According To The Value(S) In The Table Below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G134-2 (Boa) - A39-15 (Bs) Always Below 1 Ω
      G134-2 (Boa) Or A39-15 (Bs) - Body Ground Always 10 KΩ Or Higher
      G132-10 (Gnd) - Body Ground 1 Minute Or More After Disconnecting The Cable From The Negative (-) Auxiliary Battery Terminal Below 1 Ω

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ok 

    See Step  10

  10. Inspect Second Power Supply Remote Parking Circuit 
    1. Inspect The Second Power Supply Remote Parking Circuit.

      Refer To Procedure - Step 3 [11/2021 - 03/2024] , Or Refer To Procedure - Step 3 [03/2024 - ]

      Ok

      The Second Power Supply Remote Parking Circuit Is Normal.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

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

    Result: 

    Ng 

    Replace Second Power Supply Remote Parking Circuit. Refer To  Removal [11/2021 - ] 

  11. Check Harness And Connector (B1E1 Terminal) 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The G132 Second Power Supply Remote Parking Circuit Connector.
    3. Check Both The Connector Case And The Terminals For Deformation And Corrosion.

      Ok

      No Deformation Or Corrosion.

    4. Measure The Voltage According To The Value(S) In The Table Below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G132-1 (B1E1) - Body Ground Always 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ok 

    See Step  12

  12. Check Harness And Connector (Second Power Supply Remote Parking Circuit - Brake Booster With Master Cylinder Assembly) 
    1. Measure The Resistance According To The Value(S) In The Table Below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      G132-8 (Boe) - A39-14 (+Bi1) Always Below 1 Ω
      G132-8 (Boe) Or A39-14 (+Bi1) - Body Ground Always 10 KΩ Or Higher

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    See Step  10

    Result: 

    Ng 

    Repair Or Replace Harness Or Connector 

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