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).

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 an mega ohmmeter, measure the insulation resistance.
    Correct insulation resistance: 10 MΩ or higher
    
    Fig 1: Measuring Insulation Resistance Using Mega ohmmeter
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  If the resistance is less than the specified value, proceed to step ( d).
  
  HINT:
  
  If the ohmmeter is not available, perform the following simple inspection instead.
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.
    - If the electrode is dry, the spark plug is functioning. Reinstall the spark plug. Proceed to step 3.
    - If the electrode is damp, proceed to steps (c), ( d) and ( e).
3. Check the spark plug for any damage on its thread and insulator.
  If there is damage, replace the spark plug. If not, reinstall the spark plug.
  
  Recommended spark plug:
  
  Fig 2: Checking spark Plug
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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.

Safety Warning

Ignition System: Inspection

Use the Manual With the Right Hardware

When to See a Mechanic

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