🔧 Ridgeline - Ignition Coil Replacement

This procedure replaces all six coil-on-plug ignition coils on your Ridgeline. Each coil sits directly above a spark plug and supplies the high voltage needed to fire that cylinder.

Assumption: All six coils are being replaced; a confirmed single-cylinder failure can be repaired individually.

Difficulty Level: Beginner | Estimated Time: 1-1.5 hours

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⚠️ Safety & Precautions

• ⚠️ Let the engine cool completely before working near the cylinder heads.
• 🔑 Keep the ignition switched off and the key away from the vehicle.
• 🔌 Do not switch the ignition on while any ignition coil is disconnected.
• 🧹 Prevent dirt, hardware, or tools from falling into the spark-plug wells.
• 🔋 Battery disconnection is not required for this repair.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4-inch drive ratchet
• 1/4-inch drive 3-inch extension
• 1/4-inch drive 6-inch extension
• 1/4-inch drive inch-pound torque wrench rated 20-150 in-lbs
• Plastic trim removal tool
• Small flat-blade screwdriver
• Magnetic pickup tool (specialty)
• Clean shop towels
• Nitrile mechanic gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Direct-fit ignition coils - Qty: 6

Replace only the failed coil when a diagnostic test identifies one cylinder. If the original coils are being replaced because of age or repeated failures, replacing all six provides consistent output.

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📋 Before You Begin

• 🅿️ Park your Ridgeline on level ground, select Park, and apply the parking brake.
• 🌡️ Open the hood and allow the engine to become completely cool.
• 📦 Compare the new coils with the original coils before installation. The connector, mounting ear, boot length, and seal must match.
• 🔢 The rear cylinder bank, closest to the windshield, is cylinders 1-2-3 from passenger side to driver side. The front bank is cylinders 4-5-6 from passenger side to driver side.
• 📱 No infotainment service mode, scan-tool command, coding, or battery registration is required.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the Engine Cover

• Put on the safety glasses and nitrile mechanic gloves.
• Use the plastic trim removal tool to lift the engine-cover fasteners without damaging the cover.
• Lift the cover straight upward and place it safely aside.
• Use clean shop towels to wipe loose dirt away from the ignition coils and spark-plug wells.

Step 2: Locate the Six Ignition Coils

• Identify the three front-bank coils between the radiator and engine.
• Identify the three rear-bank coils between the intake manifold and windshield.
• The rear coils have less working room. Use the 1/4-inch drive 6-inch extension to reach their bolts.
• Replace one coil at a time to avoid confusion.

Step 3: Disconnect the First Coil

• Press the electrical connector release tab with your finger, then pull the connector straight away from the coil.
• If the tab is difficult to press, use the small flat-blade screwdriver to depress it gently. Do not pry against or break the connector.
• Inspect the connector for corrosion, melted plastic, loose terminals, or damaged wiring.

Step 4: Remove the Coil Retaining Bolt

• Use the 10mm socket, 1/4-inch drive ratchet, and appropriate 3-inch or 6-inch extension to remove the coil retaining bolt.
• Keep the bolt away from open engine areas. Use the magnetic pickup tool if a bolt is dropped into a confined area.

Step 5: Remove the Old Ignition Coil

• Grip the upper body of the coil. Twist it gently left and right to release the rubber boot from the spark plug.
• Pull the coil straight out of the spark-plug well.
• Inspect the boot for oil, coolant, water, cracking, or a white burn line called carbon tracking. Carbon tracking is an electrical burn path that can cause repeated misfires.
• If oil is present inside the well, stop and repair the leaking spark-plug tube seal before installing the new coil.

Step 6: Install the New Ignition Coil

• Check that the new coil's rubber boot and internal spring are fully seated.
• Lower the coil straight over the spark plug. Do not force or sharply bend the boot.
• Press downward until the boot seats firmly over the spark plug and the mounting ear rests flat against the cylinder head.
• Do not apply grease inside the coil boot unless the coil manufacturer specifically supplies and instructs you to use it.

Step 7: Tighten the Coil Bolt

• Start the retaining bolt by hand to prevent cross-threading.
• Use the 10mm socket, 1/4-inch drive extension, and inch-pound torque wrench to tighten the bolt to 12 Nm (106 in-lbs or 9 ft-lbs).
• Do not overtighten the bolt. The mounting ear and cylinder-head threads can be damaged.

Step 8: Reconnect the Electrical Connector

• Push the electrical connector straight onto the new coil until its locking tab clicks.
• Pull back gently on the connector to confirm it is locked.

Step 9: Replace the Remaining Coils

• Repeat Steps 3 through 8 for the other five coils.
• Use the 10mm socket with the 6-inch extension for the rear-bank bolts and the 3-inch extension where clearance allows.
• Verify that every coil is seated, every bolt is tightened to 12 Nm (106 in-lbs or 9 ft-lbs), and all six connectors are locked.

Step 10: Reinstall the Engine Cover

• Remove all clean shop towels and check the engine compartment for loose tools or hardware.
• Position the engine cover over its mounting points.
• Press the cover and its fasteners into place by hand. Use the plastic trim removal tool only if a fastener requires alignment.

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✅ After Repair

• 🚗 Start the engine and let it idle for two to three minutes. It should run smoothly without shaking.
• 👂 Listen for snapping or ticking sounds that could indicate a loose coil or electrical arcing.
• 💡 Confirm that the malfunction indicator lamp is not flashing. A flashing lamp indicates an active misfire; shut the engine off and recheck every connector.
• 🛣️ Take a short test drive using light and moderate acceleration, then confirm the engine remains smooth.
• 🧰 If a misfire code remains stored, it may require clearing with a compatible scan tool. A returning misfire can be caused by a spark plug, injector, wiring fault, compression problem, or incorrect replacement coil.

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💰 DIY vs Shop Cost

Shop Cost: $750-$1,250 USD (parts + labor)

DIY Cost: $300-$700 USD (six coils only)

You Save: $350-$550 USD by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 hours.

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🎯 Ready to get started?

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