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DTC C1380: Stop Light Control Relay Malfunction: Procedure

  1. CHECK STOP LIGHT OPERATION 
    1. Check that the stop lights come on when the brake pedal is depressed and go off when the brake pedal is released.

      OK

      Condition Illumination Condition
      Brake pedal depressed On
      Brake pedal released Off

    NG → See step   6 

    OK: Go to next step 

  2. READ VALUE USING TECHSTREAM (STOP LIGHT SW) 
    1. Turn the engine switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
      ABS/VSC/TRAC

      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      		 -
    6. Check that the stop light switch condition observed on the Techstream changes according to brake pedal operation.

      OK

      The Techstream displays ON and OFF according to brake pedal operation.

    NG → See step   11 

    OK: Go to next step 

  3. PERFORM ACTIVE TEST USING TECHSTREAM (STOP LIGHT RELAY) 
    1. Turn the engine switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the Techstream on.
    5. Enter the following menus: Chassis / ABS/VSC/TRAC / Active Test.
      ABS/VSC/TRAC

      Tester Display Test Part Control Range Diagnostic Note
      Stop Light Relay BRK LP relay (Brake light relay) Relay ON/OFF Observe the stop lights (the stop lights do not come on for 2 to 5 seconds).
    6. While performing the Active Test, check the illumination condition of the stop lights and "Stop Light Relay Output" in the Data List.
      ABS/VSC/TRAC

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Stop Light Relay Output BRK LP relay (Brake light relay) output / ON or OFF ON: Relay output on (Stop lights on)
      OFF: Relay output off (Stop lights off)      		 -
      RESULT

      Result Proceed to
      When Active Test performed, Data List item changes between ON and OFF and stop lights turn on and off A
      When Active Test performed, Data List item changes between ON and OFF, but stop lights do not turn on B

    B → See step   12 

    A: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (STP2 TERMINAL) 
    1. Turn the engine switch off.
    2. Disconnect the skid control ECU (master cylinder solenoid) connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY380332Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A24-45 (STP2) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU [Master Cylinder Solenoid])

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. RECONFIRM DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR [01/2012 - ] .
    2. Turn the engine switch off.
    3. Start the engine.
    4. Perform a road test.
    5. Check if the same DTC is output. Refer to DTC CHECK / CLEAR [01/2012 - ] .
      RESULT

      Result Proceed to
      DTC is not output A
      DTC is output B

    B → See step   17 

    A → See step   16 

  6. CHECK HARNESS AND CONNECTOR (+B/GND TERMINAL) 
    1. Turn the engine switch off.
    2. Disconnect the stop light control relay assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY369333Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-6 (+B) - Body ground Always 11 to 14 V
    4. 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
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Stop Light Control Relay Assembly)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the engine switch off.
    2. Disconnect the stop light control relay assembly connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY369331Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A39-2 (STP) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Stop Light Control Relay Assembly)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. INSPECT BRK LP RELAY 
    1. Remove the BRK LP relay (brake light relay) from the engine room relay block.
    2. Measure the resistance according to the value(s) in the table below.
      GTY359195Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 4 Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2 10 kΩ or higher
      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2 Below 1 Ω
      3 - 5 Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2 Below 1 Ω
      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 BRK LP Relay (Brake Light Relay)

    NG → REPLACE BRAKE LIGHT RELAY 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (STOP LIGHT CONTROL RELAY - BRK LP RELAY) 
    1. Turn the engine switch off.
    2. Disconnect the A39 stop light control relay assembly connector.
    3. Remove the BRK LP relay (brake light relay) from the engine room relay block.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A39-8 (OUT) - Engine room relay block BRK LP relay (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 

  10. CHECK HARNESS AND CONNECTOR (STOP LIGHT POWER SOURCE TERMINAL) 
    1. Remove the BRK LP relay (brake light relay) from the engine room relay block.
    2. Measure the voltage according to the value(s) in the table below.
      GTY364014Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      4 - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V
      TEXT IN ILLUSTRATION

      *a Component without BRK LP Relay (Brake Light Relay)
      (Engine Room Relay Block)

    NG → REPLACE STOP LIGHT CONTROL RELAY ASSEMBLY 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (ENGINE ROOM RELAY BLOCK BRK LP RELAY TERMINAL 3 CIRCUIT) 

  11. CHECK HARNESS AND CONNECTOR (STP TERMINAL) 
    1. Turn the engine switch off.
    2. Disconnect the skid control ECU (master cylinder solenoid) connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY384290Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      A24-7 (STP) - Body ground Brake pedal depressed 8 to 14 V
      Brake pedal released Below 1.5 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU [Master Cylinder Solenoid])

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   17 

  12. INSPECT BRK LP RELAY 
    1. Remove the BRK LP relay (brake light relay) from the engine room relay block.
    2. Measure the resistance according to the value(s) in the table below.
      GTY359195Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 4 Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2 10 kΩ or higher
      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2 Below 1 Ω
      3 - 5 Battery positive voltage is applied to terminal 1 and battery negative voltage is applied to terminal 2 Below 1 Ω
      Battery positive voltage is not applied to terminal 1 and battery negative voltage is not applied to terminal 2 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 BRK LP Relay (Brake Light Relay)

    NG → REPLACE BRAKE LIGHT RELAY 

    OK: Go to next step 

  13. CHECK HARNESS AND CONNECTOR (BRK LP RELAY POWER SOURCE TERMINAL) 
    1. Remove the BRK LP relay (brake light relay) from the engine room relay block.
    2. Measure the voltage according to the value(s) in the table below.
      GTY364014Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Condition Specified Condition
      1 - Body ground Engine switch on (IG) 8 to 14 V
      5 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Component without BRK LP relay (Brake Light Relay)
      (Engine Room Relay Block)

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. CHECK HARNESS AND CONNECTOR (STPO TERMINAL) 
    1. Turn the engine switch off.
    2. Disconnect the skid control ECU (master cylinder solenoid) connector.
    3. Measure the voltage according to the value(s) in the table below.
      GTY384291Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A24-16 (STPO) - Body ground Engine switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Skid Control ECU [Master Cylinder Solenoid])

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  15. RECONFIRM DTC 
    1. Clear the DTCs. Refer to DTC CHECK / CLEAR [01/2012 - ] .
    2. Turn the engine switch off.
    3. Check if the same DTC is output. Refer to DTC CHECK / CLEAR [01/2012 - ] .
      RESULT

      Result Proceed to
      DTC is not output A
      DTC is output B

    B → See step   18 

    A → See step   16 

  16. CHECK FOR INTERMITTENT PROBLEMS. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2012 - ] 
  17. REPLACE MASTER CYLINDER SOLENOID. Refer to  DISASSEMBLY [01/2012 - ] 
  18. REPLACE MASTER CYLINDER SOLENOID. Refer to  DISASSEMBLY [01/2012 - ] 
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