🔧 TLX - Ignition Coil Replacement

Your TLX uses coil-on-plug ignition coils (one coil per cylinder). Replacing a bad coil restores smooth idle, power, and prevents misfires that can damage the catalytic converter.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine fully cool before working around the valve cover and coils.
• ⚠️ Keep the key away from the car so it can’t be accidentally started.
• ⚠️ Avoid pulling on wiring; always unplug by the connector release tab.
• ⚠️ Battery disconnect is recommended: remove negative terminal first to reduce short-circuit risk.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" extension (1/4" drive)
• Torque wrench (inch-pound or small ft-lb)
• Small flathead screwdriver
• Pick tool
• Shop light
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1 (or Qty: 4 if replacing all)
• 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 completely.
• If disconnecting the battery: use a 10mm socket to remove the negative terminal and tuck it aside so it can’t spring back.
• Replace coils one-by-one to avoid mix-ups.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Lift up at the corners to pop it off the rubber grommets (it’s a press-fit cover).
• If your cover uses fasteners, remove them with a 10mm socket.

Step 2: Locate the ignition coils

• The coils sit on top of the valve cover, one per cylinder, in a row.
• Use a shop light so you can clearly see the connector locks and bolts.

Step 3: Unplug the coil electrical connector

• Press the connector release tab and pull the connector straight off.
• If it’s stuck, gently help the tab with a small flathead screwdriver (do not pry hard on the plastic).

Step 4: Remove the coil hold-down bolt

• Use a 10mm socket with a 1/4" drive ratchet and 6" extension to remove the bolt.
• Set the bolt aside where it won’t fall into the engine bay.

Step 5: Remove the ignition coil

• Grip the coil body and twist slightly left-right, then pull straight up to remove it.
• If the boot is stuck to the spark plug, use a pick tool carefully around the boot edge to break the seal.

Step 6: Install the new coil

• Apply a very small dab of dielectric grease inside the coil boot. (Dielectric grease is a non-conductive grease that helps prevent moisture and makes future removal easier.)
• Push the coil straight down until you feel it fully seat on the spark plug.

Step 7: Reinstall and torque the coil bolt

• Start the bolt by hand a few turns to avoid cross-threading.
• Use a torque wrench to tighten the coil bolt: Torque to 12 Nm (9 ft-lbs). (A torque wrench tightens to an exact setting so you don’t strip threads.)

Step 8: Reconnect the electrical connector

• Push the connector on until it clicks and feels locked.
• Give it a gentle tug to confirm it’s fully seated.

Step 9: Repeat for any other coils you’re replacing

• Follow the same steps for the remaining cylinders.
• If one failed, others may be close behind.

Step 10: Reinstall the engine cover and reconnect the battery

• Press the engine cover back onto the grommets until it snaps in place.
• If disconnected, reinstall the negative battery terminal using a 10mm socket and tighten snugly.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth with no flashing check engine light.
• Do a short test drive and verify normal acceleration and no hesitation.
• If the check engine light was on, use a scan tool to clear codes and confirm the misfire does not return.
• If a misfire remains on the same cylinder, the spark plug or injector may be the cause.

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💰 DIY vs Shop Cost

Shop Cost: $180-$450 (parts + labor)

DIY Cost: $60-$320 (parts only)

You Save: $120-$130 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 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.