STA Signal Circuit [12/2024 - ]: Procedure

2025 Toyota 4Runner SR5, RWDSECTION Procedure
  1. READ VALUE USING GTS (STARTER SW) 
    1. Enter the following menus: Powertrain / Engine / Data List / Starter SW.

      Powertrain > Engine > Data List 

      Tester Display
      Starter SW
    2. Read the values displayed on the GTS when the ignition switch is ON and on (START).

      OK

      GTS Display Condition Normal Condition
      Starter SW Ignition switch ON OFF
      Ignition switch START ON

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [12/2024 - ]

    Result: 

    NG 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (ECM - ST RELAY) 
    1. Disconnect the engine stop and start ECU connector.
    2. Disconnect the ECM connector.
    3. Remove the ST relay from the NO. 2 engine room relay block and junction block assembly.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A3-42 (STA) - ST relay terminal 2 Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

    Refer to PROBLEM SYMPTOMS TABLE [12/2024 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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.