🔧 ILX - Ignition Coil Replacement

Your ILX uses one ignition coil per cylinder (4 total). Replacing a weak coil can fix misfires, rough running, and a flashing check-engine light, and it’s a straightforward job with basic hand tools.

Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns.
• ⚠️ Keep the key fob away from the car while working.
• ⚠️ If you disconnect the battery, you may lose radio presets.
• ⚠️ Do not pull on wiring—only pull on connectors.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8" ratchet
• 3/8" extension (3"-6")
• Torque wrench (3/8" drive, 5-30 Nm range)
• Flat trim tool
• Small pick tool
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Replace all four - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool fully.
• If you want maximum safety: disconnect the negative battery cable using a 10mm socket. Battery negative is the “-” terminal.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Grip the cover and pull straight upward to release the rubber grommets. Use a flat trim tool gently if it feels stuck.
• Set the cover aside where it won’t get stepped on.

Step 2: Locate the ignition coils

• The coils sit on top of the engine in a row—one per cylinder—with an electrical connector on each coil.

Step 3: Unplug the coil electrical connector

• Press the connector lock tab, then pull the connector straight off the coil.
• If the tab is stubborn, use a small pick tool to gently help lift the lock. Be gentle—plastic gets brittle.

Step 4: Remove the coil hold-down bolt

• Use a 10mm socket, 3/8" ratchet, and 3/8" extension to remove the single bolt holding the coil down.
• Set the bolt aside so it doesn’t fall into the engine bay.

Step 5: Remove the ignition coil

• Twist the coil slightly left/right to break the seal, then pull straight up to remove it.
• If it’s stuck, keep twisting while pulling—avoid prying hard on the valve cover.

Step 6: Prep and install the new coil

• Put a very small smear of dielectric grease inside the new coil boot. (Dielectric grease is a silicone grease that helps prevent moisture and makes future removal easier.)
• Push the new coil straight down until it fully seats on the spark plug.

Step 7: Reinstall the hold-down bolt and torque it

• Thread the bolt in by hand first (to avoid cross-threading), then snug it with a 10mm socket.
• Tighten with a torque wrench (a tool that tightens to an exact force): Torque to 12 Nm (9 ft-lbs).

Step 8: Reconnect the coil connector

• Push the connector on until you feel/hear a “click.”
• Gently tug to confirm it’s locked.

Step 9: Repeat for the remaining coils

• Replace coils one at a time so nothing gets mixed up.

Step 10: Reinstall the engine cover

• Line up the cover with the mounting points and press down firmly until it seats.
• If you disconnected the battery, reconnect it using a 10mm socket and snug it securely.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth.
• If the check-engine light was on, it may need a scan tool to clear stored codes after the repair.
• Do a short test drive and re-check that there are no warning lights and no misfire feel.
• Quick re-check: make sure every coil connector is fully clicked in.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $120-$280 (parts only)

You Save: $130-$170 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.7-1.2 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.