🔧 Ignition Coils - Replacement

On your Corolla, the ignition coils sit on top of the spark plugs and are simple to replace. This job is usually done when you have misfires, rough idle, or coil failure codes. You’ll remove the engine cover, unplug each coil, swap them one at a time, and reinstall everything carefully.

Difficulty Level: Beginner | Estimated Time: 0.5-1 hour

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⚠️ Safety & Precautions

• Make sure the engine is completely cool before starting.
• Turn the ignition off and remove the key/fob from the vehicle.
• Disconnect the negative battery terminal before unplugging coils.
• Do not pull on the wiring harness; release the connector lock first.
• Keep dirt out of the spark plug wells.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• Ratchet
• Short extension
• Trim removal tool
• Torque wrench
• Needle-nose pliers
• Safety glasses
• Gloves

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil set - Qty: 4
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on a level surface and set the parking brake.
• Let the engine cool down fully.
• Open the hood and support it securely.
• Disconnect the negative battery cable using a 10mm socket.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Use your hands to pull upward evenly on the plastic engine cover.
• Set it aside in a safe place.

Step 2: Disconnect the battery

• Use a 10mm socket and ratchet to loosen the negative battery terminal.
• Move the cable away from the battery so it cannot spring back.

Step 3: Unplug each ignition coil

• One coil at a time, release the connector tab with your fingers or needle-nose pliers.
• Pull the connector straight back.
• Work one coil at a time.

Step 4: Remove the ignition coils

• Use a 10mm socket and short extension to remove each coil retaining bolt.
• Pull the coil straight up and out of the spark plug tube.
• If a coil is stuck, twist it gently while lifting.

Step 5: Install the new ignition coils

• Compare the new coil to the old one before installing.
• If desired, apply a small amount of dielectric grease inside the coil boot.
• Push the new coil straight down until fully seated.
• Install the retaining bolt and Torque to 9 Nm (80 in-lbs).

Step 6: Reconnect the electrical connectors

• Push each connector on until it clicks.
• Make sure each plug is locked in place.

Step 7: Reinstall the battery connection and engine cover

• Reconnect the negative battery terminal with a 10mm socket.
• Install the engine cover by pressing it down evenly.

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✅ After Repair

• Start the engine and let it idle.
• Check for rough running, warning lights, or misfire symptoms.
• If the check engine light stays on, scan for codes and clear them after confirming the repair.
• Take a short test drive and recheck engine idle quality.

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💰 DIY vs Shop Cost

Shop Cost: $220-$450 (parts + labor)

DIY Cost: $80-$220 (parts only)

You Save: $140-$230 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1 hour.

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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.