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Home >> Lexus >> 2010 >> LX 570 >> Repair and Diagnosis >> Accessories & Equipment >> Exterior Lights >> Lighting (Exterior) (Diagnostic Codes & Symptom Tests) >> Lighting System >> Stop Light does not Illuminate >> Procedure

Stop Light does not Illuminate: Procedure

  1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) 
    1. Using the Techstream, read the Data List.
      MAIN BODY

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light SW Stop light switch/ON or OFF ON: Brake pedal depressed
      OFF: Brake pedal released      		 -

      OK

      On the Techstream screen, each item changes between ON and OFF according to above chart.

    NG → See step   10 

    OK: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BATTERY AND BODY GROUND) 
    1. Disconnect the A39 stop light relay connector.
      Fig 1: Identifying A39 Stop Light Relay Connector
      GTY135007Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-6 (+B) - Body ground Always 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A39-4 (GND) - Body ground Always Below 1 Ω

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - STOP LIGHT SWITCH) 
    1. Disconnect the A30 stop light switch connector.
      Fig 2: Identifying A30 Stop Light Switch And A39 Relay Connectors
      GTY153577Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the A39 relay connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A30-1 - A39-2 (STP) Always Below 1 Ω
      A30-1 - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. INSPECT BRAKE LIGHT RELAY (BRK LP) 
    1. Remove the brake light relay from the engine room relay block.
      Fig 3: Identifying Brake Light Relay Circuit
      GTY153552Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage not applied to terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω
      3 - 4 Battery voltage not applied to terminals 1 and 2 Below 1 Ω
      Battery voltage applied to terminals 1 and 2 10 kΩ or higher

    NG → REPLACE BRAKE LIGHT RELAY 

    OK: Go to next step 

  5. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BRAKE LIGHT RELAY) 
    Fig 4: Identifying Brake Light Relay And A39 Connector Terminals
    GTY135312Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the brake light relay from the engine room relay block.
    2. Disconnect the A39 stop light control relay connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-6 (+B) - Body ground Always 11 to 14 V

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A39-8 (OUT) - Brake light relay terminal 4 Always Below 1 Ω
      A39-8 (OUT) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY - STOP LIGHT AND BODY GROUND) 
    Fig 5: Identifying Brake Light Relay And Rear Combination Light Connector Terminals
    GTY153795Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the brake light relay from the engine room relay block.
    2. Rear Combination Light:
      1. Disconnect the K4 and L3 light connectors.
      2. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        for LH 

        for RH 

        Tester Connection Condition Specified Condition
        Brake light relay terminal 3 - K4-5 (STP) Always Below 1 Ω
        K4-3 (E) - Body ground
        K4-5 (STP) - Body ground Always 10 kΩ or higher
        Tester Connection Condition Specified Condition
        Brake light relay terminal 3 - L3-5 (STP) Always Below 1 Ω
        L3-3 (E) - Body ground
        L3-5 (STP) - Body ground Always 10 kΩ or higher
      Fig 6: Identifying Brake Light Relay And S4 High Mount Stop Light Connector
      GTY153796Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. High Mount Stop Light:
      1. Disconnect the S4 light connector.
      2. Measure the resistance according to the value(s) in the table below.

        Standard Resistance

        Tester Connection Condition Specified Condition
        Brake light relay terminal 3 - S4-1 (B) Always Below 1 Ω
        S4-2 (E) - Body ground
        S4-1 (B) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY - BATTERY) 
    1. Remove the brake light relay from the engine room relay block.
      Fig 7: Checking Harness And Connector (Brake Light Relay - Battery)
      GTY139810Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      Brake light relay terminal 1 - Body ground Engine switch on (IG) 11 to 14 V
      Engine switch off Below 1 V
      Brake light relay terminal 5 - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (BRAKE LIGHT RELAY - SKID CONTROL ECU) 
    Fig 8: Identifying Brake Light Relay And A24 ECU Connector
    GTY153794Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Remove the brake light relay from the engine room relay block.
    2. Disconnect the A24 ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      Brake light relay terminal 2 - A24-16 (STP0) Always Below 1 Ω
      Brake light relay terminal 2 - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. CHECK STOP LIGHT CONTROL RELAY 
    1. Temporarily replace the stop light control relay with a new or normally functioning one. Refer to ON-VEHICLE INSPECTION .
    2. Check the stop light operation.

      OK

      Stop light operation is normal.

    NG → See step   14 

    OK → See step   13 

  10. INSPECT STOP LIGHT SWITCH 
    1. Remove the stop light switch. Refer to INSPECTION .
      Fig 9: Inspecting Stop Light Switch
      GTY142233Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Switch Condition Specified Condition
      1 - 2 Switch pin released Below 1 Ω
      1 - 2 Switch pin pushed in 10 kΩ or higher

    NG → See step   15 

    OK: Go to next step 

  11. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - BATTERY) 
    1. Disconnect the A30 stop light switch connector.
      Fig 10: Identifying A30 Stop Light Switch Connector
      GTY141494Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      A30-2 - Body ground Always 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  12. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - STOP LIGHT SWITCH) 
    1. Disconnect the A30 stop light switch connector.
      Fig 11: Identifying A30 Stop Light Switch And 2B ECU Connectors
      GTY153554Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the 2B ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A30-1 - 2B-22 (STP) Always Below 1 Ω
      A30-1 - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → REPLACE MAIN BODY ECU 

  13. REPLACE STOP LIGHT CONTROL RELAY. Refer to  ON-VEHICLE INSPECTION 
  14. REPLACE MASTER CYLINDER SOLENOID (SKID CONTROL ECU). Refer to  REMOVAL - Step 9 
  15. REPLACE STOP LIGHT SWITCH. Refer to  REMOVAL - Step 1 
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