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Turn Signal Light Circuit: Procedure

  1. CHECK TURN SIGNAL LIGHT (OPERATION) 
    1. Turn the engine switch on (IG).
    2. When the turn signal light switch is operated, check that the corresponding turn signal lights flash.

      HINT: 

      The front and rear turn signal lights share the same drive circuit. Therefore, if either the front or rear turn signal lights do not come on, there may be a problem in the circuit between the turn signal flasher and a bulb, or the circuit between a bulb and body ground.

      Result

      Result Proceed to
      Neither left nor right turn signal lights flash A
      Left turn signal lights do not flash B
      Right turn signal lights do not flash C

    C → See step   11 

    B → See step   6 

    A: Go to next step 

  2. PERFORM ACTIVE TEST USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Body No. 3 / Active Test.
    5. Check that the turn signal lights operate.
      BODY NO. 3 (MAIN BODY ECU LH)

      Tester Display Test Part Control Range Diagnostic Note
      Turn Light RH RH side turn signal lights ON/OFF -
      Turn Light LH LH side turn signal lights ON/OFF -

      OK

      Turn signal lights flash.

    NG → See step   3 

    OK → See step   17 

  3. INSPECT FUSE (LH-IG, TURN-HAZ) 
    1. Remove the LH-IG fuse from the cowl side junction block LH.
    2. Remove the TURN-HAZ fuse from the No. 1 engine room junction block.
    3. Measure the resistance of the fuses.

      Standard Resistance

      Below 1 Ω

    NG → REPLACE FUSE 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (POWER SOURCE) 
    1. Disconnect the J30 flasher assembly connector.
      Fig 1: Identifying J30 Connector Terminals
      GTY279226Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Turn Signal Flasher Assembly)
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J30-7 (E) - Body ground Always Below 1 Ω
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      J30-4 (B) - Body ground Always 11 to 14 V
      J30-1 (IG) - Body ground Engine switch on (IG) 11 to 14 V

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. REPLACE TURN SIGNAL FLASHER ASSEMBLY 
    1. Temporarily replace the turn signal flasher assembly with a new or known good one. Refer to COMPONENTS .
    2. Check that the turn signal lights flash.

      OK

      Turn signal lights flash.

    NG → See step   17 

    OK → END 

  6. PERFORM ACTIVE TEST USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Body No. 3 / Active Test.
    5. Check that the turn signal lights LH.
      BODY NO. 3 (MAIN BODY ECU LH)

      Tester Display Test Part Control Range Diagnostic Note
      Turn Light LH Turn signal lights LH ON/OFF -

      OK

      Turn signal lights flash.

    NG → See step   7 

    OK → See step   17 

  7. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - BODY GROUND) 
    1. Disconnect the LA main body ECU LH connector.
      Fig 2: Identifying LA Connector Terminals
      GTY276865Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Main Body ECU LH)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      LA-16 (TL) - Body ground Always 11 to 14 V

    NG → See step   10 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (TURN SIGNAL FLASHER ASSEMBLY - HEADLIGHT) 
    1. Disconnect the J30 flasher assembly connector.
      Fig 3: Identifying J30 And B12 Connector Terminals
      GTY274539Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Turn Signal Flasher Assembly)
      *2 Front view of wire harness connector
      (to Headlight Assembly)
    2. Disconnect the B12 headlight assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J30-3 (LL) - B12-9 Always Below 1 Ω
      J30-3 (LL) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. REPLACE TURN SIGNAL FLASHER ASSEMBLY 
    1. Temporarily replace the turn signal flasher assembly with a new or known good one. Refer to COMPONENTS .
    2. Check that the turn signal lights flash.

      OK

      Turn signal lights flash.

    NG → REPLACE MAIN BODY ECU LH (COWL SIDE JUNCTION BLOCK LH) 

    OK → END 

  10. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - TURN SIGNAL FLASHER ASSEMBLY) 
    1. Disconnect the LA main body ECU LH connector.
      Fig 4: Identifying J30 And LA Connector Terminals
      GTY258364Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Turn Signal Flasher Assembly)
      *2 Front view of wire harness connector
      (to Main Body ECU LH)
    2. Disconnect the J30 flasher connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      LA-16 (TL) - J30-5 (EL) Always Below 1 Ω
      LA-16 (TL) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   16 

  11. PERFORM ACTIVE TEST USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Body No. 3 / Active Test.
    5. Check that the turn signal lights RH operate.
      BODY NO. 3 (MAIN BODY ECU LH)

      Tester Display Test Part Control Range Diagnostic Note
      Turn Light RH Turn signal lights RH ON/OFF -

      OK

      Turn signal lights flash.

    NG → See step   12 

    OK → See step   17 

  12. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - BODY GROUND) 
    1. Disconnect the LA main body ECU LH connector.
      Fig 5: Identifying LA Connector Terminals
      GTY276873Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Main Body ECU LH)
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      LA-15 (TR) - Body ground Always 11 to 14 V

    NG → See step   15 

    OK: Go to next step 

  13. CHECK HARNESS AND CONNECTOR (TURN SIGNAL FLASHER ASSEMBLY - HEADLIGHT) 
    1. Disconnect the J30 turn signal flasher assembly connector.
      Fig 6: Identifying J30 And B2 Connector Terminals
      GTY274541Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Turn Signal Flasher Assembly)
      *2 Front view of wire harness connector
      (to Headlight Assembly)
    2. Disconnect the B2 headlight assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      J30-2 (LR) - B2-9 Always Below 1 Ω
      J30-2 (LR) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  14. REPLACE TURN SIGNAL FLASHER ASSEMBLY 
    1. Temporarily replace the turn signal flasher assembly with a new or known good one. Refer to COMPONENTS .
    2. Check that the turn signal lights flash.

      OK

      Turn signal lights flash.

    NG → REPLACE MAIN BODY ECU LH (COWL SIDE JUNCTION BLOCK LH) 

    OK → END 

  15. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU LH - TURN SIGNAL FLASHER ASSEMBLY) 
    1. Disconnect the LA main body ECU LH connector.
      Fig 7: Identifying J30 And LA Connector Terminals
      GTY258365Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Turn Signal Flasher Assembly)
      *2 Front view of wire harness connector
      (to Main Body ECU LH)
    2. Disconnect the J30 turn signal flasher assembly connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      LA-15 (TR) - J30-6 (ER) Always Below 1 Ω
      LA-15 (TR) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   16 

  16. REPLACE TURN SIGNAL FLASHER ASSEMBLY. Refer to  COMPONENTS 
  17. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE 
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