🔧 Cadenza - Ignition Coil Replacement

Ignition coils sit on top of the spark plugs and create the high voltage needed to fire each cylinder. On your Cadenza’s 3.3L V6, the front bank coils are easy to reach, but the rear bank coils typically require removing the upper intake manifold (plenum) for access.

Difficulty Level: Advanced | Estimated Time: 2.5-4.5 hours

Assumption: Rear bank coils require upper intake manifold removal.

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⚠️ Safety & Precautions

• ⚠️ Work on a fully cool engine to avoid burns.
• ⚠️ Disconnect the negative battery terminal to prevent electrical damage and accidental shorting.
• ⚠️ Keep dirt out of the intake ports—cover openings immediately once the manifold is off.
• ⚠️ Do not pull on wiring; release connectors by their locking tabs.
• ⚠️ Fuel vapors may be present near the intake area—no smoking/open flames.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 3/8" drive ratchet
• 3/8" drive torque wrench (10–30 Nm range)
• 3" socket extension
• 6" socket extension
• Universal swivel joint (3/8" drive)
• Phillips screwdriver
• Flat trim tool
• Needle-nose pliers
• Shop towels
• Masking tape
• Permanent marker
• Brake cleaner spray
• Flashlight
• Nitrile gloves
• Safety glasses

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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
• Throttle body gasket - Qty: 1
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and let the engine cool completely.
• Use masking tape and a marker to label any hoses/connectors you unplug so they go back to the same spot.
• Disconnect the negative battery terminal using a 10mm socket.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Lift the cover upward to release the rubber grommets (no tools usually needed).
• Set it aside where it won’t get stepped on.

Step 2: Remove the air intake ducting (to create room)

• Use a Phillips screwdriver to loosen the hose clamps on the intake tube.
• Use a flat trim tool to gently pop any plastic clips without breaking them.
• Remove the intake tube/duct and set it aside.

Step 3: Replace the front bank ignition coils (easy-access side)

• Unplug each coil electrical connector by pressing the lock tab (use a flat trim tool gently if stuck).
• Remove the coil hold-down bolt with a 10mm socket, ratchet, and 3" extension.
• Twist the coil slightly, then pull straight up to remove it.
• Apply a very small smear of dielectric grease inside the rubber boot of the new coil.
• Install the new coil straight down until fully seated, then install the bolt.
• Torque to 9 Nm (80 in-lbs) using a torque wrench (a torque wrench is a tool that tightens bolts to an exact safe tightness).
• Reconnect the electrical connector until it clicks.

Step 4: Remove the upper intake manifold (plenum) to access the rear bank coils

• Unplug the throttle body connector and any nearby sensors using your hands or a flat trim tool if needed.
• Disconnect small vacuum hoses carefully using needle-nose pliers (move clamps back, then twist hose to break it free).
• Remove the throttle body mounting bolts using a 10mm socket and ratchet.
• Torque note for reassembly: Throttle body bolts Torque to 10 Nm (89 in-lbs).
• Remove the upper intake manifold bolts/nuts using a 12mm socket, ratchet, and extensions (use a universal swivel joint where access is tight).
• Lift the manifold up and off. Immediately place shop towels into the exposed intake openings to keep hardware/dirt out.
• Torque note for reassembly: Upper intake manifold fasteners Torque to 21 Nm (15 ft-lbs).

Step 5: Replace the rear bank ignition coils

• Remove the shop towels only when you’re ready to work, and keep openings covered whenever you pause.
• Unplug each rear coil connector by pressing the lock tab.
• Remove each coil bolt using a 10mm socket, ratchet, and extension.
• Remove the coil by twisting slightly and pulling straight up.
• Install the new coil(s), then Torque to 9 Nm (80 in-lbs) with a torque wrench.
• Reconnect each electrical connector until it clicks.

Step 6: Reinstall the intake manifold and throttle body with new gaskets

• Remove the old gaskets and wipe mating surfaces using shop towels and a light spray of brake cleaner spray (spray the towel, not directly into openings).
• Install the new upper intake manifold gasket set in the correct positions.
• Set the manifold in place carefully without pinching hoses/wiring.
• Tighten manifold fasteners evenly, then Torque to 21 Nm (15 ft-lbs) using a torque wrench.
• Install the new throttle body gasket, reinstall the throttle body, then Torque to 10 Nm (89 in-lbs).
• Reconnect all vacuum hoses and electrical connectors (use your labels to confirm routing).

Step 7: Reinstall the air intake ducting and engine cover

• Reinstall the intake tube and tighten clamps with a Phillips screwdriver.
• Press the engine cover back onto its grommets until it seats.
• Reconnect the negative battery terminal using a 10mm socket.

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✅ After Repair

• Start the engine and let it idle for 2–3 minutes. Listen for hissing (vacuum leak) and watch for a check engine light.
• If the idle is rough, recheck every coil connector and any vacuum hose you touched.
• Do a short test drive, then recheck that no warning lights return.
• If you had a misfire code before, clear codes with a scan tool after the repair (optional but recommended).

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💰 DIY vs Shop Cost

Shop Cost: ₹12,000-₹35,000 (parts + labor, depending on number of coils)

DIY Cost: ₹3,000-₹18,000 (parts only)

You Save: ₹9,000-₹17,000 by doing it yourself!

Shop labor rates vary but typically run ₹1,000-₹2,500/hour. This repair takes a shop approximately 2.5-4.5 hours.

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🎯 Ready to get started?

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