How to Replace Ignition Coils on a 2012 Honda Accord (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools list, parts, safety tips, and 12 Nm (9 ft-lbs) torque spec for 2008, 2009, 2010, 2011, 2012
How to Replace Ignition Coils on a 2012 Honda Accord (Fix Misfires & Rough Idle)
Step-by-step coil-on-plug replacement with tools list, parts, safety tips, and 12 Nm (9 ft-lbs) torque spec for 2008, 2009, 2010, 2011, 2012
đź”§ Accord - Ignition Coil Replacement
Your Accord uses a coil-on-plug ignition system (each spark plug has its own ignition coil). Replacing a bad coil can fix misfires, rough idle, flashing check engine light, and poor acceleration.
Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours
⚠️ Safety & Precautions
- ⚠️ Work on a cool engine to avoid burns (coils sit on top of the cylinder head).
- ⚠️ Keep the key out of the ignition so the engine can’t be started accidentally.
- ⚠️ Disconnecting the battery negative cable is recommended to prevent accidental shorts.
- ⚠️ Don’t pull on wiring—only on connectors and the coil body.
đź”§ Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 3/8" ratchet
- 6" socket extension
- 10mm wrench
- Torque wrench (5-30 Nm range)
- Small flathead screwdriver
- Needle-nose pliers
- Shop light
- Nitrile gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1 (single) or 4 (replace all four)
- Dielectric grease - Qty: 1
đź“‹ Before You Begin
- Park on level ground and let the engine cool completely.
- Open the hood and keep the key away from the car.
- If you choose to disconnect the battery: use a 10mm wrench to remove the negative cable and move it aside so it can’t spring back.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover (if equipped)
- Look at the top of the engine. If there’s a plastic cover, remove its fasteners with a 10mm socket and 3/8" ratchet.
- Lift the cover off and set it aside.
Step 2: Locate the ignition coils
- The coils are the 4 identical units lined up on top of the engine, each with an electrical connector.
- Take a quick photo for reference.
Step 3: Unplug the coil electrical connector
- Press the connector release tab and pull the connector straight off.
- If it’s stuck, gently help the tab with a small flathead screwdriver (don’t pry hard).
- A “connector” is the plastic plug with wires that clicks into the coil.
Step 4: Remove the ignition coil hold-down bolt
- Use a 10mm socket, 6" socket extension, and 3/8" ratchet to remove the single bolt holding the coil down.
- Set the bolt somewhere safe (it’s easy to lose).
Step 5: Pull the coil out
- Grip the coil body and twist it slightly left-right to break the seal, then pull straight up.
- If needed, use needle-nose pliers only to help lift the coil by its sturdy body—not the wiring.
Step 6: Prep and install the new coil
- Put a tiny smear of dielectric grease inside the rubber boot (the rubber “sock” on the bottom of the coil). Dielectric grease helps keep moisture out and makes future removal easier.
- Push the new coil straight down onto the spark plug until it fully seats.
Step 7: Reinstall the coil bolt and torque it
- Thread the bolt in by hand first (to avoid cross-threading).
- Tighten with a 10mm socket and 3/8" ratchet, then use a torque wrench: Torque to 12 Nm (9 ft-lbs).
Step 8: Plug the connector back in
- Push the connector on until you feel/hear a click.
- Give it a gentle tug to confirm it’s locked.
Step 9: Repeat for the other cylinders (if replacing more than one)
- Repeat Steps 3-8 for each coil you’re replacing.
- Replace all four if high mileage.
Step 10: Reinstall engine cover and reconnect battery
- Reinstall the engine cover using a 10mm socket and 3/8" ratchet (snug, do not over-tighten).
- If disconnected, reconnect the battery negative cable using a 10mm wrench.
âś… After Repair
- Start the engine and let it idle for 1-2 minutes. It should run smooth with no shaking.
- Check that the check engine light is not flashing. If it is flashing, shut the engine off and re-check each connector is fully clicked in.
- If the check engine light stays on, the stored code may need to be cleared after the fix (a scan tool can do this).
- Take a short test drive and re-check for any warning lights or rough running.
đź’° DIY vs Shop Cost
Shop Cost: $250-$600 (parts + labor, depending on how many coils)
DIY Cost: $60-$320 (parts only, depending on how many coils)
You Save: $190-$280 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.
🎯 Ready to get started?
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