🔧 Sequoia - Ignition Coil Replacement

On your Sequoia, each cylinder has its own ignition coil (coil-on-plug). Replacing a bad coil can fix misfires, rough running, and a flashing check-engine light, and it’s a straightforward job with basic hand tools.

Difficulty Level: Intermediate | Estimated Time: 1.0-2.0 hours

---

⚠️ Safety & Precautions

• ⚠️ Let the engine cool fully; coils sit on a hot cylinder head.
• ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
• ⚠️ Don’t pull on wiring; release the connector lock first.
• ⚠️ If the check-engine light was flashing, avoid driving until repaired (can damage the catalytic converters).

---

🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 1/4" drive ratchet
• 6" extension (1/4" drive)
• Torque wrench (in-lb or low-range Nm)
• Trim clip removal tool
• Flathead screwdriver (small)
• Needle-nose pliers
• Flashlight

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-8
• Dielectric grease - Qty: 1
• Ignition coil electrical connector lock clip - Qty: 0-8

---

📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool completely.
• Disconnect the negative battery cable using a 10mm socket.
• If you’re replacing just one coil: note which cylinder is misfiring (from your code scan) so you don’t mix up locations.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover (if equipped)

• Remove the engine appearance cover fasteners using a 10mm socket and 1/4" drive ratchet.
• Lift the cover off and set it aside.

Step 2: Make space to reach the coils (as needed)

• For tighter access near the air intake tube, loosen hose clamps carefully using a flathead screwdriver (small).
• Release any plastic clips using a trim clip removal tool.
• Move the intake tube/ducting slightly aside without cracking it. Don’t force cold plastic.

Step 3: Unplug the ignition coil connector

• Find the coil on top of the valve cover; it looks like a small module going straight down into the engine.
• Press the connector release tab and pull the connector straight off.
• If the tab is stubborn, gently help it with a flathead screwdriver (small) (do not pry hard).

Step 4: Remove the coil retaining bolt

• Remove the coil bolt using a 10mm socket, 6" extension (1/4" drive), and 1/4" drive ratchet.
• Set the bolt aside where it won’t fall into the engine bay.

Step 5: Remove the ignition coil

• Twist the coil slightly to break the seal, then pull straight up by hand.
• If it’s stuck, wiggle gently—do not use a metal pry tool on the valve cover.

Step 6: Prep and install the new coil

• Put a small dab of dielectric grease inside the new coil boot. (A “boot” is the rubber sleeve that seals to the spark plug.)
• Push the new coil straight down until it fully seats on the spark plug.

Step 7: Reinstall the coil bolt and torque it

• Install the bolt by hand first to avoid cross-threading.
• Tighten using a torque wrench (in-lb or low-range Nm).
• Torque to 9 Nm (80 in-lbs).

Step 8: Reconnect the electrical connector

• Push the connector on until it clicks.
• Lightly tug the connector to confirm it’s locked.

Step 9: Repeat for any other coils, then reassemble

• Repeat Steps 3–8 for each coil you’re replacing.
• Reinstall any intake ducting/clips using the flathead screwdriver (small), needle-nose pliers, and trim clip removal tool as needed.
• Reinstall the engine cover using the 10mm socket.

Step 10: Reconnect the battery

• Reconnect the negative battery cable using a 10mm socket.

---

✅ After Repair

• Start the engine and listen for smooth idle (no shaking).
• If you had a check-engine light, clear the codes and confirm the misfire does not return.
• Road test for 10–15 minutes, then recheck for warning lights.
• If it still misfires on the same cylinder, the next common items are the spark plug, injector, or wiring/connector damage.

---

💰 DIY vs Shop Cost

Shop Cost: $350-$900 (parts + labor)

DIY Cost: $60-$520 (parts only)

You Save: $290-$380 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0-2.0 hours.

---

🎯 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.