🔧 Yukon Denali - Ignition Coil Replacement

Your Yukon Denali uses one ignition coil per cylinder to create the high-voltage spark the engine needs. Replacing a weak or failed coil can fix misfires, rough idle, flashing check-engine light, and loss of power.

Difficulty Level: Beginner | Estimated Time: 0.8-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine to avoid burns (coils sit near hot parts).
• ⚠️ Disconnect the negative battery cable if you’ll be unplugging multiple coils at once.
• ⚠️ Don’t pull on the wiring; press the connector lock and pull the plug body.
• ⚠️ Keep dirt out of the spark plug wells; wipe the area before removing wires.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" socket extension (1/4")
• Torque wrench (in-lb)
• Small flat trim tool
• Needle-nose pliers
• Shop towels
• 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: 8 if replacing all)
• Dielectric grease - Qty: 1
• Ignition coil wiring connector pigtail (optional) - Qty: 1 (only if connector is broken/brittle)

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Let the engine fully cool.
• If you’re doing more than one coil: use a 10mm socket to disconnect the negative battery cable and move it aside.
• Tip: Replace coils one at a time to avoid mix-ups.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grab the cover at the corners and pull straight up to release the rubber grommets.
• Set it aside where it won’t get scratched.

Step 2: Locate the coil you’re replacing

• The coils sit on top of the valve covers, with a short plug wire running from each coil to its spark plug.
• Use a shop towel to wipe dust off around the coil and wire ends.

Step 3: Unplug the coil electrical connector

• Use a small flat trim tool to gently lift the connector lock (a small safety tab), then press the release and pull the connector off.
• Tip: Wiggle the connector—don’t yank.

Step 4: Remove the spark plug wire from the coil

• Grip the boot (the thick rubber end), twist it a little to break it free, then pull it off the coil.
• If it’s tight, use needle-nose pliers gently on the boot only (not the wire).

Step 5: Unbolt and remove the coil

• Use a 10mm socket, 6" extension, and 1/4" ratchet to remove the coil mounting bolts.
• Lift the coil straight off the valve cover bracket.

Step 6: Install the new coil

• Set the new coil in place and start the bolts by hand (this prevents cross-threading).
• Use a torque wrench (in-lb) with a 10mm socket to tighten the coil bolts: Torque to 89 in-lb (10 Nm).

Step 7: Reconnect the spark plug wire

• Apply a pea-sized amount of dielectric grease inside the wire boot (this helps prevent moisture and makes future removal easier).
• Push the boot onto the coil until you feel it seat firmly.
• Make sure the wire routing matches the original path and isn’t touching sharp edges or hot exhaust parts.

Step 8: Reconnect the coil electrical connector

• Push the connector on until it clicks.
• Re-engage the connector lock so it can’t back out.

Step 9: Reinstall the engine cover

• Line up the cover over its mounting points and press down firmly to seat the grommets.

Step 10: Reconnect the battery (if disconnected)

• Use a 10mm socket to tighten the negative battery terminal securely.

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✅ After Repair

• Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
• If the check-engine light was flashing before, confirm it is no longer flashing.
• Road-test for 10 minutes and recheck for a check-engine light.
• If you have a scan tool, clear stored misfire codes and confirm none return.
• Tip: If misfire stays, check the plug and wire.

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💰 DIY vs Shop Cost

Shop Cost: $180-$450 (single coil) / $700-$1,400 (all 8 coils)

DIY Cost: $35-$90 (single coil) / $280-$720 (all 8 coils)

You Save: $145-$680 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.5 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.