ECU Power Source Circuit [12/2024 - ]: Procedure

2025 Toyota 4Runner SR5, 4WDSECTION Procedure
  1. CHECK HARNESS AND CONNECTOR (PARKING ASSIST ECU - AUXILIARY BATTERY AND BODY GROUND) 
    1. Disconnect the K59 parking assist ECU connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      K59-1 (GND1) - Body ground Always Below 1 Ω
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      K59-4 (IG) - K59-1 (GND1) Ignition switch ON 11 to 14 V
      Ignition switch off Below 1 V

      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.