🔧 Grand Cherokee - Ignition Coil Replacement

Your Grand Cherokee uses a coil-on-plug ignition system (each cylinder has its own ignition coil mounted directly on the spark plug). Replacing a bad coil fixes misfires, rough idle, flashing check-engine lights, and loss of power.

Difficulty Level: Beginner | Estimated Time: 0.5-1.5 hours

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⚠️ Safety & Precautions

• Work on a cool engine; coils sit near hot components.
• Turn ignition fully OFF and keep the key/fob away from the vehicle while unplugging coils.
• If you disconnect the battery, you may lose radio presets.
• Do not pull on wiring; unplug connectors by the locking tab.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" drive ratchet
• 6" extension (1/4" drive)
• Torque wrench (in-lb or low-range Nm)
• Small flathead screwdriver
• 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: 6 if replacing all)
• Dielectric grease - Qty: 1 (optional)

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📋 Before You Begin

• Park on level ground and set the parking brake.
• Open the hood and let the engine cool fully.
• If you want maximum safety: disconnect the negative battery cable using a 10mm socket.
• Dielectric grease is a non-conductive grease that helps seal moisture at the rubber boot (use a tiny amount).

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the engine cover

• Grip the plastic engine cover firmly and pull straight up to pop it off its rubber grommets.
• Set it aside where it won’t get stepped on.

Step 2: Locate the coil you’re replacing

• Each ignition coil is a small module with an electrical connector and one mounting bolt.
• Do one coil at a time.

Step 3: Unplug the coil electrical connector

• Use a small flathead screwdriver only if needed to gently lift the connector lock tab.
• Press the release and pull the connector straight back (do not yank the wires).

Step 4: Remove the coil mounting bolt

• Use a 10mm socket, 1/4" drive ratchet, and 6" extension to remove the bolt.
• Place the bolt somewhere safe so it doesn’t fall into the engine bay.

Step 5: Remove the ignition coil

• Twist the coil slightly left/right to break the seal, then pull straight up.
• If it’s stubborn, keep twisting gently—don’t pry hard on plastic parts.

Step 6: Install the new ignition coil

• If using it, put a tiny smear of dielectric grease inside the rubber boot (not on the metal spring).
• Push the new coil straight down until it fully seats on the spark plug.
• Reinstall the mounting bolt by hand first to avoid cross-threading.
• Tighten with a torque wrench: Torque to 9 Nm (80 in-lb).

Step 7: Reconnect the electrical connector

• Push the connector on until it clicks/locks.
• Give it a gentle tug to confirm it’s fully latched.

Step 8: Reinstall the engine cover

• Line it up with the grommets and press straight down until it snaps into place.

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✅ After Repair

• If you disconnected the battery, reconnect it using a 10mm socket.
• Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
• Road test for 10 minutes and verify the check-engine light stays off.
• If the check-engine light was on, you may need to clear codes with an OBD2 scanner (optional).
• If it still misfires, the issue may be the spark plug, injector, or wiring at that cylinder.

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💰 DIY vs Shop Cost

Shop Cost: $180-$450 (parts + labor, depending on how many coils)

DIY Cost: $35-$330 (parts only)

You Save: $145-$120+ by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.5 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.