🔧 Traverse - Ignition Coil Replacement

Replacing the ignition coils on your Traverse restores strong spark to the engine and can fix misfires, rough idle, poor acceleration, or a flashing check-engine light. The 3.6L V6 has six ignition coils, one mounted directly on top of each spark plug.

Difficulty Level: Intermediate | Estimated Time: 1.5-3 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting. The intake, rear cylinder bank area, and exhaust-side components can burn you.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils to prevent accidental shorts.
• ⚠️ Work gently around plastic electrical connectors. Older connectors can crack if forced.
• ⚠️ Keep dirt and debris out of the spark plug wells. Debris can fall into the engine if a spark plug is removed later.
• ⚠️ The rear ignition coils require intake manifold removal on the 3.6L V6. Replace the intake manifold gaskets if the manifold is removed.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 8mm socket
• 7mm socket
• 1/4-inch drive ratchet
• 3/8-inch drive ratchet
• 3-inch extension
• 6-inch extension
• Torque wrench inch-pound
• Torque wrench foot-pound
• Flat trim removal tool
• Small flat-blade screwdriver
• Needle-nose pliers
• Clean shop towels
• Painter's tape
• Permanent marker
• Safety glasses
• Nitrile gloves
• OBD-II scan tool

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-6
• Upper intake manifold gasket set - Qty: 1
• Dielectric grease - Qty: 1

Note: Replace only the failed coil if one cylinder has a confirmed misfire. If mileage is high and several coils are original, replacing all six can save repeat labor.

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📋 Before You Begin

• Park your Traverse on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool fully.
• Use painter's tape and a permanent marker to label connectors and hoses before disconnecting them. This makes reassembly easier.
• Disconnect the negative battery cable with a 10mm socket and move it aside so it cannot spring back to the terminal.
• If you are replacing rear bank coils, plan to remove the upper intake manifold and replace the manifold gaskets.
• An OBD-II scan tool is a small plug-in tool that reads and clears engine fault codes. Use it before starting if you want to identify the misfiring cylinder.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Put on safety glasses and nitrile gloves.
• Lift the plastic engine cover straight upward by hand to release it from the rubber mounting grommets.
• Set the cover aside where it will not be stepped on.
• Pull upward evenly.

Step 2: Disconnect the Battery

• Use a 10mm socket and 3/8-inch drive ratchet to loosen the negative battery cable nut.
• Remove the negative cable from the battery terminal and place it aside.
• Do not let the cable touch the battery post while you work.

Step 3: Identify the Coil Location

• The 3.6L V6 has three front ignition coils that are easier to reach and three rear ignition coils under the upper intake manifold.
• Each ignition coil has one electrical connector and one small retaining bolt.
• If using an OBD-II scan tool, read the misfire code. Codes P0301 through P0306 point to cylinders 1 through 6.
• Use painter's tape and a permanent marker to label any connector you disconnect.

Step 4: Replace a Front Ignition Coil

• Use a small flat-blade screwdriver to gently lift the connector lock tab if needed. A lock tab is the small plastic latch that holds the plug in place.
• Press the electrical connector release and unplug the connector from the ignition coil by hand.
• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove the ignition coil retaining bolt.
• Twist the ignition coil gently by hand, then pull it straight upward out of the spark plug well.
• Compare the old and new ignition coils to make sure the shape and connector match.
• Apply a small pea-sized amount of dielectric grease inside the rubber boot of the new coil. Dielectric grease is an electrical-safe grease that helps seal out moisture.
• Push the new ignition coil straight down until it seats fully on the spark plug.
• Install the retaining bolt with a 10mm socket and torque wrench. Torque to 10 Nm (89 in-lbs)
• Reconnect the electrical connector until it clicks.
• Do not overtighten small bolts.

Step 5: Remove Air Intake Duct for Rear Coil Access

• Use a 7mm socket and 1/4-inch drive ratchet to loosen the hose clamp at the throttle body.
• Use a 7mm socket and 1/4-inch drive ratchet to loosen the hose clamp at the air filter housing.
• Use needle-nose pliers to release any small hose clamps attached to the intake duct.
• Remove the air intake duct by hand and set it aside.
• Cover open intake areas with clean shop towels to keep dirt out.

Step 6: Disconnect Upper Intake Manifold Attachments

• Use painter's tape and a permanent marker to label vacuum hoses and electrical connectors connected to the upper intake manifold.
• Use a small flat-blade screwdriver to release connector locks gently, then unplug the connectors by hand.
• Use needle-nose pliers to release hose clamps, then remove attached hoses by hand.
• Move the wiring and hoses aside carefully without stretching them.

Step 7: Remove the Upper Intake Manifold

• Use an 8mm socket, 6-inch extension, and 1/4-inch drive ratchet to loosen the upper intake manifold bolts evenly.
• Remove the bolts and keep them organized in order.
• Lift the upper intake manifold upward carefully by hand.
• Place clean shop towels over the open intake ports immediately. Intake ports are the openings that feed air into the engine.
• Remove the old upper intake manifold gaskets by hand.
• Clean the gasket seating surfaces with clean shop towels only. Do not scrape debris into the intake ports.
• Cover every open port.

Step 8: Replace Rear Ignition Coils

• Use a small flat-blade screwdriver to gently lift each connector lock tab if needed.
• Press the electrical connector release and unplug the connector from the ignition coil by hand.
• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove the ignition coil retaining bolt.
• Twist the ignition coil gently by hand, then pull it straight upward.
• Apply a small pea-sized amount of dielectric grease inside the rubber boot of the new coil.
• Install the new ignition coil straight down onto the spark plug until fully seated.
• Install the retaining bolt with a 10mm socket and torque wrench. Torque to 10 Nm (89 in-lbs)
• Reconnect the electrical connector until it clicks.

Step 9: Reinstall the Upper Intake Manifold

• Remove the clean shop towels from the intake ports. Count them to make sure none are left behind.
• Install the new upper intake manifold gaskets by hand into the manifold grooves.
• Lower the upper intake manifold into place by hand without pinching wires or hoses.
• Start all intake manifold bolts by hand first.
• Use an 8mm socket, 6-inch extension, and inch-pound torque wrench to tighten the bolts gradually in a crisscross pattern. Torque to 10 Nm (89 in-lbs)
• Reconnect all hoses and electrical connectors using your labels.
• Hand-start bolts first.

Step 10: Reinstall the Air Intake Duct

• Remove any clean shop towels from the throttle body or intake openings.
• Install the air intake duct by hand onto the throttle body and air filter housing.
• Use a 7mm socket and 1/4-inch drive ratchet to tighten the hose clamps snugly.
• Reconnect any small hoses using needle-nose pliers to position the clamps.

Step 11: Reconnect the Battery and Reinstall Cover

• Install the negative battery cable onto the battery terminal.
• Use a 10mm socket and 3/8-inch drive ratchet to tighten the negative battery cable nut snugly. Do not overtighten.
• Press the engine cover down by hand until it snaps onto the rubber grommets.

Step 12: Clear Codes and Test Run

• Plug the OBD-II scan tool into the diagnostic port under the driver side of the dash.
• Turn the ignition on without starting the engine.
• Use the OBD-II scan tool to clear stored misfire codes if repairs are complete.
• Start the engine and let it idle.
• Listen for hissing noises, which can mean a vacuum leak at the intake manifold or hose.

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✅ After Repair

• ✅ Let the engine idle for 2-3 minutes and confirm it runs smoothly.
• ✅ Check that every connector and hose you labeled is reconnected.
• ✅ Look around the upper intake manifold for anything loose or pinched.
• ✅ Take a short test drive and confirm the check-engine light does not flash.
• ✅ Recheck for diagnostic trouble codes with the OBD-II scan tool after the drive.
• ✅ If the engine still misfires, do not keep driving with a flashing check-engine light. That can damage the catalytic converter.

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💰 DIY vs Shop Cost

Shop Cost: $250-$850 depending on how many coils are replaced and whether rear coils are included

DIY Cost: $45-$420 parts only depending on coil quantity and gasket set

You Save: $150-$450 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1-2.5 hours.

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🎯 Ready to get started?

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