2005 Toyota Highlander Limited, AWDFACTORY OEM SERVICE PROCEDURE

Ignition System (2AZ-FE): Inspection

NOTE: In this section, the terms "cold" and "hot" refer to the temperature of the coils. "Cold" means approximately -10°C (14°F) to 50°C (122°F). "Hot" means approximately 50°C (122°F) to 100°C (212°F). 
  1. INSPECT SPARK PLUG 
    NOTE:
    • Do not use a wire brush for cleaning. 
    • Do not attempt to adjust the electrode gap of a used spark plug. 
    1. Check the electrode.
      1. Using a mega ohmmeter, measure the insulation resistance.

        Correct insulation resistance: 10 MΩ or higher 

      If the resistance is less than the specified value, proceed to step (d).

      HINT:

      If a mega ohmmeter is not available, do the following simple inspection instead.

      Fig 1: Measuring Insulation Resistance (Electrode)
      G02598027Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Alternative inspection method:
      1. Quickly accelerate the engine to 4,000 RPM 5 times.
      2. Remove the spark plug.
      3. Visually check the spark plug.
      4. If the electrode is dry, the spark plug is functioning. Proceed to step 2.
      5. If the electrode is damp, proceed to step (c), (d), and (e).
      6. Install the spark plug.
      Fig 2: Checking Spark Plug
      G02598028Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Check the spark plug for any damage on its thread and insulator.

      If there is damage, replace the spark plug.

      Recommended spark plug: 

      RECOMMENDED SPARK PLUG

      DENSO made SK20R11
      NGK made IFR6A11
    4. Check the spark plug electrode gap.

      Maximum electrode gap for used spark plug: 1.3 mm (0.051 in.) 

      If the gap is greater than the maximum, replace the spark plug.

      Correct electrode gap for new spark plug: 1.0 to 1.1 mm (0.039 to 0.043 in.) 

      NOTE: If adjusting the gap of a new spark plug, bend only the base of the ground electrode. Do not touch the tip. Never attempt to adjust the gap on a used plug. 
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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.