🔧 Altima - Ignition Coil Replacement

Replacing the ignition coils on your Altima is a straightforward top-of-engine repair. The ignition coils sit on top of the spark plugs and create the high voltage needed to fire each cylinder.

Assumption: This guide covers replacing the four coil-on-plug ignition coils on the 2.0L VC-Turbo engine.

Difficulty Level: Beginner | Estimated Time: 30-60 minutes

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before starting; the turbocharged engine bay can stay hot for a long time.
• ⚠️ Disconnect the negative battery cable before unplugging ignition coils to prevent electrical shorts.
• ⚠️ Do not pull on wiring. Press the connector lock and pull from the connector body only.
• ⚠️ Replace coils one at a time if possible, so the connectors and coil positions do not get mixed up.
• ⚠️ If the check engine light is flashing, avoid driving until repaired because misfires can damage the catalytic converter.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4-inch drive ratchet
• 3-inch extension
• Torque wrench inch-pound range
• Plastic trim removal tool
• Small flathead screwdriver
• OBD2 scan tool
• Battery terminal wrench 10mm
• Nitrile gloves
• Safety glasses
• Shop towels

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Ignition coil - Qty: 1-4
• Dielectric grease - Qty: 1 small tube

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📋 Before You Begin

• 🅿️ Park your Altima on level ground, shift to Park, and set the parking brake.
• ❄️ Let the engine cool until you can comfortably touch the plastic engine cover.
• 🔋 Use a 10mm battery terminal wrench to disconnect the negative battery cable and move it aside so it cannot spring back onto the battery post.
• 🧠 If replacing only one coil, use an OBD2 scan tool first to identify the misfiring cylinder code, such as P0301, P0302, P0303, or P0304.
• 📌 Dielectric grease is a non-conductive silicone grease used to help seal the rubber boot from moisture.

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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.
• Use your hands to lift the plastic engine cover upward from its rubber mounting grommets.
• If it feels stuck, use a plastic trim removal tool near the mounting points and gently pry upward.
• Set the cover aside where it will not be stepped on.
• Lift straight up, not sideways.

Step 2: Locate the Ignition Coils

• Look along the top of the engine for four identical ignition coils.
• Each coil has an electrical connector and one retaining bolt.
• Use a shop towel to wipe dirt away from the area around each coil before removal.
• This helps keep debris from falling into the spark plug wells.

Step 3: Unplug the Ignition Coil Connector

• Use your thumb to press the locking tab on the coil connector.
• If the tab is stiff, use a small flathead screwdriver to gently help depress the lock.
• Pull the connector straight back by the plastic body.
• Do not pull on the wires.
• Gentle pressure prevents broken connectors.

Step 4: Remove the Coil Retaining Bolt

• Use a 10mm socket, 3-inch extension, and 1/4-inch drive ratchet to remove the ignition coil retaining bolt.
• Place the bolt in a safe spot so it does not fall into the engine bay.

Step 5: Remove the Old Ignition Coil

• Grip the ignition coil body with your hand.
• Twist it gently left and right to loosen the rubber boot from the spark plug.
• Pull the coil straight upward out of the spark plug well.
• If the boot sticks, keep twisting gently while pulling upward.
• Inspect the old coil boot for oil, cracks, burn marks, or white tracking lines.

Step 6: Prepare the New Ignition Coil

• Compare the new ignition coil to the old one before installing it.
• Use a shop towel to make sure the spark plug well opening is clean and dry.
• Apply a very small amount of dielectric grease inside the end of the rubber boot only.
• Do not put grease on the metal electrical contact.
• A pea-sized amount is enough.

Step 7: Install the New Ignition Coil

• Push the new coil straight down into the spark plug well by hand.
• You should feel the boot seat onto the spark plug.
• Line up the coil mounting hole with the bolt hole on the valve cover.

Step 8: Tighten the Coil Retaining Bolt

• Start the bolt by hand first to avoid cross-threading.
• Use a 10mm socket, 3-inch extension, and torque wrench inch-pound range to tighten the bolt.
• Torque to 6.9 Nm (61 in-lbs).
• Do not overtighten; the valve cover threads can be damaged.

Step 9: Reconnect the Coil Connector

• Push the electrical connector onto the new coil until it clicks.
• Gently tug the connector body by hand to confirm it is locked.
• If replacing more than one coil, repeat Steps 3 through 9 for each remaining coil.

Step 10: Reinstall the Engine Cover

• Align the engine cover with the rubber mounting grommets.
• Press down firmly by hand over each mounting point until the cover seats fully.

Step 11: Reconnect the Battery

• Use a 10mm battery terminal wrench to reconnect the negative battery cable.
• Tighten the terminal until it is snug and cannot rotate by hand.
• Do not overtighten the battery terminal clamp.

Step 12: Clear Codes and Test Idle

• Use an OBD2 scan tool to clear stored misfire codes if the check engine light was on.
• Start the engine and let it idle for 2-3 minutes.
• Listen for smooth idle and confirm the check engine light stays off.

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✅ After Repair

• ✅ Take a gentle 10-15 minute test drive with light acceleration first.
• ✅ If the engine runs smoothly, do one moderate acceleration to confirm the misfire is gone.
• ✅ Recheck for warning lights after the test drive using an OBD2 scan tool.
• ✅ If the same cylinder misfire returns, the spark plug, fuel injector, wiring, or compression may need diagnosis.
• ✅ If oil is found inside a spark plug well, the valve cover sealing area may need repair before installing more coils.

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💰 DIY vs Shop Cost

Shop Cost: $220-$650 (parts + labor)

DIY Cost: $45-$320 (parts only)

You Save: $175-$330 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?

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