Security Indicator Light Circuit: Procedure

2013 Toyota Tundra Base, 5.7L Eng VIN WSECTION Procedure
  1. PERFORM ACTIVE TEST USING TECHSTREAM (SECURITY INDICATOR) 
    1. Operate the Techstream according to the steps on the display and select "Active Test".
      MAIN BODY

      Tester Display Test Part Control Range Diagnostic Note
      Security Indicator Security indicator ON/OFF -

      OK

      Security indicator illuminates.

    NG → See step   2 

    OK → See step   3 

  2. CHECK HARNESS AND CONNECTOR (ACCESSORY METER - MAIN BODY ECU) 
    Fig 1: Checking Harness And Connector (Accessory Meter -- Main Body ECU)
    GTY197833Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Disconnect the J1 main body ECU connector.
    2. Disconnect the K20 accessory meter connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Condition Specified Condition
      K20-16 (MHTR) - J1-4 (IND) Always Below 1 Ω
      K20-16 (MHTR) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   4 

  3. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE  
  4. REPLACE ACCESSORY METER. Refer to  REMOVAL 
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.