Owners of other Toyota, Lexus or Scion vehicles such as the Yaris, Matrix, Prius, Camry, RAV4, Sienna, Tacoma, Tundra, FJ Cruiser, Venza, Highlander, Avalon, Sequoia, Land Cruiser, IS 250, ES 350, GS 350, tC, xB, xD, iQ and FR-S may also find these DIY instructions to be helpful.

The OEM spark plugs in this 2014 Corolla are Denso part number SC20HR11 (3444) Iridium.

A few compatible replacement spark plugs with their part numbers are as follows: NGK (4912) ILKAR7B11, Pulstar GG1H10, Bosch (9621) VR7NII33X, Toyota 90919-01253, Autolite XP5683 Iridium or Autolite APP5683.

The tools needed to complete this procedure include a flathead screwdriver, a 14mm spark plug socket or a 9/16" spark plug socket, an extension bar, a 3/8" drive ratcheting wrench and a tube of dielectric grease.

Set the plastic engine cover aside in a safe place.

If the car been driven recently, I'd recommend allowing the engine to cool off for at least an hour or two to prevent from burning your fingers or hands.

Press in the release tab on the black plastic electrical connector before sliding it off the end of the ignition coil housing.

If the release tab is to stiff to push in with your fingers, use a flathead screwdriver to push it down.

Loosen the single bolt that holds the ignition coil housing in place by turning it counterclockwise with a 10mm socket and 1/4" drive ratcheting wrench.

Set the 10mm bolt aside in a safe place.

Rotate the ignition coil back and forth a few times to make sure that the rubber dust boot at the end is not stuck or "frozen" to the top of the old spark plug.

Attach the 14mm spark plug socket or a 9/16" spark plug socket) to the extension bar and the 3/8" drive ratcheting wrench.

I personally used a 6 point 9/16" spark plug socket.

Loosen the old spark plug by turning it counterclockwise. Try to avoid using excessive force.

If the spark plug won't turn, spray in some penetrating oil such as PB Blaster, Liquid Wrench or Kano Kroil and wait 15-30 minutes or more before trying again. If you don't have any penetrating oil, try spraying some WD-40 or just warm up the engine for a few minutes to expand the metal engine block.

Once the spark plug is loose, detach the ratcheting wrench.

Continue spinning out the old spark plug with your finger tips on the extension bar.

Carefully lift the old spark plug out of the well.

If the end of the old spark plug looks ashy white, the plugs may have been exposed to high temperatures such as engine overheating or they are the incorrect heat range for your driving conditions and/or environment.

If the old spark plugs are dark grey or covered in black soot, the engine might be burning oil and should be checked by a professional mechanic.

If you have a spark plug gap gauge, check the gap on the new spark plugs. They should already be pre-gapped to the correct setting from the factory. The box should list the correct specifications.

The OEM spark plugs are Denso SC20HR11 iridium which should last up to 100,000 miles. The OEM Denso plugs should be gapped to .044" from the factory.

Push the new spark plug in to the socket and lower it down in to the well.

Spin in the spark plug by hand a few turns in the clockwise direction to prevent it from becoming cross threaded.

Attach the 3/8" drive ratcheting wrench to the extension bar and tighten the new spark plug in the clockwise direction to just a tiny bit past the point when you feel the crush washer collapse.

I don't have the service manual for the 2014 11th generation Toyota Corolla, but the torque specification for tightening the spark plugs in the service manual for the 10th generation (2009, 2010, 2011, 2012 & 2013) Toyota Corolla with the exact same 2ZR-FE 1.8L I4 engine is 15 lb-ft (or 20 Nm).

If you are re-installing the old spark plugs, tighten them to just a small fraction of a turn past hand tight.

Try to avoid using excessive force to prevent from cracking the new spark plug or stripping the aluminum threads.

The dielectric grease will help prevent corrosion and help keep out any moisture or debris.

Lower the ignition coil down in to the spark plug well.

Rotate the ignition coil back and forth a few times to help spread the dielectric grease.

Tighten the bolt in the clockwise direction with the 10mm socket and 1/4" drive ratcheting wrench until it is snug.

(The Toyota shop manual specification for tightening the 10mm ignition coil bolts is 7 lb-ft or 10 N*m.)

Try to avoid over tightening the ignition coil bolt to prevent from cracking the plastic housing.

Push the electrical connector straight on to the ignition coil housing until it clicks securely in to place.

Push the plastic engine cover back in to place.

Start the engine and listen closely for any strange sounds that might indicate a problem such as a loose spark plug or disconnected ignition coil power plug.

Be sure to record the spark plug change in your car's service records.

For more, check out my other 2014-2018 Toyota Corolla DIY Repair & Maintenance Guides.