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Home >> Lexus >> 2025 >> NX 350h >> Repair and Diagnosis >> External Pages >> Different car >> Section 96 (Electronically Controlled Brake System - Diagnostic Codes (3 Of 3), Symptom Tests & Circuit Tests) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for Gasoline 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

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  1. CHECK DTC 
    1. Check the details of the DTCs.

      Chassis > Brake/EPB > Trouble Codes 

      HINT: 

      When DTC P0571-11, P0571-12 and/or P0571-13 are output together with DTC C1380-7E, inspect and repair the trouble areas indicated by DTC P0571-11, P0571-12 and/or P0571-13 first.

      Result

      Result Proceed to
      P0571-11, P0571-12, P0571-13 or C1380-7E is output A
      C1380-7E is output B

    Result: 

    A 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

    Result: 

    B 

    See step  2

  2. CHECK STOP LIGHT ILLUMINATION STATUS 
    1. With the brake pedal released, check the illumination status of the brake lights.

      Result

      Result Proceed to
      The stop lights are illuminated. A
      The stop lights are not illuminated. B

    Result: 

    B 

    See step  8

    Result: 

    A 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU OUTPUT CIRCUIT) 
    1. Make sure that there is no looseness at the locking part and the connecting part of the connector.
      GTY1060074Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Semiconductor Power Integration ECU)

      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
      A77-8 (ACC) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CHECK STOP LIGHT ILLUMINATION STATUS 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A77 semiconductor power integration ECU connector.

      Procedure2

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    4. Check the illumination status of the brake lights.

      Result

      Result Proceed to
      The stop lights are illuminated. A
      The stop lights are not illuminated. B

      Post-procedure1

    5. None

    Result: 

    B 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    A 

    See step  5

  5. CHECK STOP LIGHT ILLUMINATION STATUS 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the A77 semiconductor power integration ECU connector.

      Procedure2

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    5. Check the illumination status of the brake lights.

      Result

      Result Proceed to
      The stop lights are illuminated. A
      The stop lights are not illuminated. B

      Post-procedure1

    6. None

    Result: 

    A 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LIGHT CIRCUIT) 

    Result: 

    B 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

  6. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU CIRCUIT) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.

      Procedure2

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    4. Measure the voltage according to the value(s) in the table below.
      GTY1060074Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Semiconductor Power Integration ECU)

      Standard Voltage

      Tester Connection Condition Specified Condition
      A77-8 (ACC) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. None

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - BRAKE ACTUATOR ASSEMBLY) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the A77 semiconductor power integration ECU connector.

      Procedure2

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A77-8 (ACC) or A36-27 (STPO) - Body ground and other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    6. None

    Result: 

    OK 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. CHECK STOP LIGHT OPERATION 
    1. Check that the stop lights come on when the brake pedal is depressed.

      OK

      The stop lights illuminate.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  10

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (STOP LIGHT SIGNAL INPUT CIRCUIT) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.

      Procedure2

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    4. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A36-43 (STP2) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. None

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  10. CHECK STOP LIGHT OPERATION 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.

      Procedure2

    3. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    4. Check that the stop lights come on when the brake pedal is depressed.

      OK

      The stop lights illuminate.

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    5. None

    Result: 

    OK 

    REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - REAR COMBINATION LIGHT ASSEMBLY LH) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.

      Procedure2

    4. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    5. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G109-7 (STP) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    6. None

    Result: 

    OK 

    GO TO LIGHTING SYSTEM (REAR COMBINATION LIGHT ASSEMBLY LH (STOP LIGHT CIRCUIT)) 

    Refer to "Left or right stop light (rear combination light assembly) does not illuminate" of problem symptoms table.

    w/ Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    w/o Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    Result: 

    NG 

    See step  12

  12. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - REAR COMBINATION LIGHT ASSEMBLY RH) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.
    4. Disconnect the G18 rear combination light assembly RH connector.

      Procedure2

    5. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      G18-7 (STP) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    7. None

    Result: 

    OK 

    GO TO LIGHTING SYSTEM (REAR COMBINATION LIGHT ASSEMBLY RH (STOP LIGHT CIRCUIT)) 

    Refer to "Left or right stop light (rear combination light assembly) does not illuminate" of problem symptoms table.

    w/ Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    w/o Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    Result: 

    NG 

    See step  13

  13. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - REAR LIGHT ASSEMBLY LH) 
    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 A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.
    4. Disconnect the G18 rear combination light assembly RH connector.
    5. Disconnect the P5 rear light assembly LH connector.
    6. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    7. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      P5-3 (B) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO LIGHTING SYSTEM (REAR LIGHT ASSEMBLY LH (STOP LIGHT CIRCUIT)) 

    Refer to "Left or right stop light (rear light assembly) does not illuminate" of problem symptoms table.

    w/ Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    w/o Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    Result: 

    NG 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - REAR LIGHT ASSEMBLY RH) 
    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 A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.
    4. Disconnect the G18 rear combination light assembly RH connector.
    5. Disconnect the P5 rear light assembly LH connector.
    6. Disconnect the P4 rear light assembly RH connector.
    7. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

    8. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      P4-3 (B) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO LIGHTING SYSTEM (REAR LIGHT ASSEMBLY RH (STOP LIGHT CIRCUIT)) 

    Refer to "Left or right stop light (rear light assembly) does not illuminate" of problem symptoms table.

    w/ Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    w/o Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    Result: 

    NG 

    See step  15

  15. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - CENTER STOP LIGHT ASSEMBLY) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.
    4. Disconnect the G18 rear combination light assembly RH connector.
    5. Disconnect the P5 rear light assembly LH connector.
    6. Disconnect the P4 rear light assembly RH connector.
    7. Disconnect the c1 center stop light assembly connector.

      Procedure2

    8. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    9. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      c1-2 (B2) - Body ground Brake pedal depressed 11 to 14 V

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    10. None

    Result: 

    OK 

    GO TO LIGHTING SYSTEM (CENTER STOP LIGHT ASSEMBLY (STOP LIGHT CIRCUIT)) 

    Refer to "High mounted stop light does not illuminate" of problem symptoms table.

    w/ Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    w/o Automatic Headlight Beam Level Control System: Refer to PROBLEM SYMPTOMS TABLE [11/2021 - 03/2022] , or refer to PROBLEM SYMPTOMS TABLE [03/2022 - 03/2024] , or refer to PROBLEM SYMPTOMS TABLE [03/2024 - ]

    Result: 

    NG 

    See step  16

  16. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR POWER INTEGRATION ECU - REAR COMBINATION LIGHT ASSEMBLY LH) 

    Procedure1

    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.

      Pre-procedure1

    2. Disconnect the A36 skid control ECU (brake actuator assembly) connector.
    3. Disconnect the G109 rear combination light assembly LH connector.
    4. Disconnect the G18 rear combination light assembly RH connector.
    5. Disconnect the P5 rear light assembly LH connector.
    6. Disconnect the P4 rear light assembly RH connector.
    7. Disconnect the c1 center stop light assembly connector.
    8. Disconnect the A77 semiconductor power integration ECU connector.

      Procedure2

    9. Check both the connector case and the terminals for deformation and corrosion.

      OK

      No deformation or corrosion.

      Procedure3

    10. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A77-18 (OUT) - G109-7 (STP) Always Below 1 Ω
      A77-18 (OUT) or G109-7 (STP) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

      Post-procedure1

    11. None

    Result: 

    OK 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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