LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2025 >> NX 250 FWD >> 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 C1380-7E: Stop Lamp Relay Actuator Stuck On [11/2021 - ] >> Procedure

Dtc C1380-7E: Stop Lamp Relay Actuator Stuck On [11/2021 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check Stop Light Illumination Status 
    1. With The Brake Pedal Released, Check The Illumination Status Of The Stop Lights.

      Result

      Result Proceed To
      The Stop Lights Are Illuminated. A
      The Stop Lights Are Not Illuminated. B

    Result: 

    B 

    See Step  5

    Result: 

    A 

    See Step  2

  2. Check Brake Actuator Assembly 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connectors.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The A38 No. 2 Skid Control ECU (Brake Actuator Assembly) 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
      A38-37 (Stp2) - Body Ground Stop Light Switch Assembly Off
      (Brake Pedal Released)      		 Below 1.5 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Replace Brake Actuator Assembly. Refer To  Removal [11/2021 - ] 

    Result: 

    Ng 

    See Step  3

  3. Check Semiconductor Power Integration ECU 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connectors.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The A77 Semiconductor Power Integration ECU 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
      A38-37 (Stp2) - Body Ground Always Below 1.5 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Replace Semiconductor Power Integration ECU. Refer To  Removal [11/2021 - ] 

    Result: 

    Ng 

    See Step  4

  4. Check For Short To +B In Stp2 Circuit 
    1. Check That There Is No Short To +B In The Stp2 Circuit (Wire Harnesses, Connectors And Stop Lights).

      Ok

      No Short To +B.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

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

    Result: 

    Ng 

    Repair Or Replace Malfunctioning Part 

  5. Check Brake Actuator Assembly 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connectors.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The A38 No. 2 Skid Control ECU (Brake Actuator Assembly) 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
      A38-11 (Stp) - Body Ground Stop Light Switch Assembly On (Brake Pedal Depressed) 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Replace Brake Actuator Assembly. Refer To  Removal [11/2021 - ] 

    Result: 

    Ng 

    See Step  6

  6. Check Semiconductor Power Integration ECU 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connectors.

      Ok

      The Connector Is Securely Connected.

    2. Disconnect The A77 Semiconductor Power Integration ECU 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
      A38-11 (Stp) - Body Ground Stop Light Switch Assembly On (Brake Pedal Depressed) 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Replace Semiconductor Power Integration ECU. Refer To  Removal [11/2021 - ] 

    Result: 

    Ng 

    See Step  7

  7. Check Harness And Connector (Stop Light Switch Assembly - Brake Actuator Assembly) 
    1. Make Sure That There Is No Looseness At The Locking Part And The Connecting Part Of The Connector.
      GTY1059727Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *A Component With Harness Connected
      (Stop Light Switch Assembly)

      Ok

      The Connector Is Securely Connected.

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

      Standard Voltage

      Tester Connection Condition Specified Condition
      A37-2 (L) - Body Ground Stop Light Switch Assembly On (Brake Pedal Depressed) 11 To 14 V

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Repair Or Replace Harness Or Connector 

    Result: 

    Ng 

    See Step  8

  8. Check For Short To Ground In Stp Circuit 
    1. Check That There Is No Short To Ground In The Stp Circuit (Wire Harnesses, Connectors And Ecus)

      Ok

      There Is No Short To Ground.

      Result

      Proceed To
      Ok
      Ng

    Result: 

    Ok 

    Replace Stop Light Switch Assembly. Refer To  Removal [11/2021 - ] 

    Result: 

    Ng 

    Repair Or Replace Malfunctioning Part 

scientia non olet · About LEMON Manuals