2007 Lexus RX 400h FWDFACTORY OEM SERVICE PROCEDURE

Ignition System: Inspection

  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 megaohmmeter, measure the insulation resistance.

        Correct insulation resistance: 

        10 MΩ or higher 

        If the resistance is less then the specified value, proceed to step (b).

        HINT:

        If a megaohmmeter is not available, perform the following simple inspection instead.

      Fig 1: Measuring Insulation Resistance
      G05201128Courtesy 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.
        Fig 2: Identifying Spark Plug Electrode
        G04962918Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

        Result 

        ELECTRODE CONDITION RESULT REFERENCE

        Electrode condition Next step
        Dry Go to next step
        Wet Proceed to step (c)
      4. Reinstall the spark plug.
    3. Check the spark plug for any damage to its threads and insulator.

      If there is any damage, replace the spark plug.

      Recommended spark plug: 

      SPARK PLUG REFERENCE CHART

      DENSO made SK20R11
      NGK made IFR6A11
      Fig 3: Identifying Spark Plug
      G04962919Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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.) 

      Fig 4: Checking Spark Plug Electrode Gap
      G05201131Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    5. Clean the spark plugs.

      If the electrode has traces of wet carbon, clean the electrode with a spark plug cleaner and then dry it.

      Air pressure: 

      Blow 588 kPa (6 kgf/cm 2  , 85 psi) 

      Duration: 

      20 seconds or less 

      HINT:

      If there are traces of oil, remove them with gasoline before using the spark plug cleaner.

    Fig 5: Cleaning Spark Plugs
    G04962921Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Factory Service Tools

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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.

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