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Home >> Lexus >> 2019 >> ES 350 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 245 (Engine Control System (A25A-FKS) - Diagnostic Codes (08 Of 12)) >> SFI System >> DTC P0703-12: Brake Switch "B" Circuit Short to Battery [08/2020 - 08/2021] >> Procedure

DTC P0703-12: Brake Switch "B" Circuit Short to Battery [08/2020 - 08/2021]: Procedure

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  1. READ VALUE USING TECHSTREAM (STOP LIGHT SW) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Data List / Stop Light SW.

      Powertrain > Engine > Data List 

      Tester Display
      Stop Light SW
    5. Read the Data List displayed on the Techstream.

      OK

      Techstream Display Measurement Item/Range (Display) Normal Condition
      Stop Light SW Stop light switch assembly status: ON or OFF
      • ON: Brake pedal depressed
      • OFF: Brake pedal released

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [08/2020 - ] 

    Result: 

    NG 

    See step  2

  2. CHECK STOP LIGHT SWITCH ASSEMBLY INSTALLATION 
    1. Check the stop light switch installation.

      Refer to INSTALLATION [06/2018 - ]

      OK

      Stop light switch is installed correctly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    SECURELY REINSTALL STOP LIGHT SWITCH ASSEMBLY. Refer to  INSTALLATION [06/2018 - ] 

    Result: 

    OK 

    See step  3

  3. CHECK TERMINAL VOLTAGE (STP VOLTAGE) 
    GTY946860Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    *a Brake pedal depressed *b Brake pedal released
    *c Front view of wire harness connector
    (to ECM)    		 - -
    1. Disconnect the ECM connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Brake Pedal Operation Specified Condition
      A28-21 (STP) - Body ground Released Below 1.5 V
      Depressed 7.5 to 14 V

      HINT: 

      If there is a short in the STP terminal circuit, there may be a malfunction in the circuit of a connected ECU.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [08/2020 - 08/2021] 

    Result: 

    NG 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH ASSEMBLY - ECM) 
    1. Disconnect the stop light switch assembly connector.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A80-3 (L) or A28-21 (STP) - Other terminals Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE STOP LIGHT SWITCH ASSEMBLY. Refer to  REMOVAL [06/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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