How to Replace the Ignition Coil on a 2012 Acura TSX
If you’ve noticed a misfire, rough idle, or a sudden drop in fuel efficiency, the culprit is often the 2012 Acura TSX ignition coil. Fortunately, swapping the coil out is a job many DIY‑enthusiasts tackle with just a few tools and a bit of patience. Below is a step‑by‑step guide that walks you through everything from safety checks to confirming the repair was successful.
Tools and Parts You’ll Need
- Replacement ignition coil (OEM or high‑quality aftermarket)
- Socket set with 10 mm and 13 mm sockets
- Torque wrench (optional but recommended)
- Flat‑head screwdriver
- Dielectric grease
- Gloves and safety glasses
Having the right parts on hand prevents the need to pause mid‑job, which can be frustrating when you’re already under the hood.
Safety First: Disconnect the Battery
Before you lift the engine cover, disconnect the negative terminal of the battery. This simple step eliminates the risk of shorting any electrical components while you work. Wait a minute or two after disconnecting—this lets any stored charge in the system dissipate.
Locating the Ignition Coils on a 2012 Acura TSX
The 2012 TSX uses a four‑cylinder engine with a coil‑on‑plug (COP) design, meaning each cylinder has its own coil mounted directly on the spark plug. The coils sit atop the engine, just behind the valve cover, and are held in place by a single bolt.
Removing the Faulty Coil
- Remove the engine cover by pulling upward; it’s usually secured with a few plastic clips.
- Locate the coil you intend to replace. If you’re addressing a specific misfire code, the faulty coil will correspond to that cylinder number.
- Disconnect the electrical plug by pressing the release tab and pulling the connector straight out.
- Using a 10 mm socket, loosen and remove the bolt securing the coil to the spark plug.
- Gently twist the coil upward to disengage it from the plug, then pull it free.
Take note of the coil’s orientation; keeping it the same way up can save you from reinstalling it incorrectly.
Installing the New Ignition Coil
- Apply a thin layer of dielectric grease to the inside of the coil’s boot. This helps ensure a good seal and eases future removal.
- Seat the new coil onto the spark plug, pressing down until you feel it click into place.
- Insert the bolt and tighten it to the manufacturer’s specification—typically around 8 Nm. Over‑tightening can crack the coil housing.
- Reconnect the electrical plug, making sure the latch clicks securely.
- Replace the engine cover and reattach any clips you removed.
Repeat these steps for any additional coils you’re swapping out. Many owners replace all four at once to maintain balanced performance.
Testing the Installation
Reconnect the battery’s negative terminal and start the engine. The idle should be smooth, and the check‑engine light should stay off. For added confidence, use an OBD‑II scanner to verify that the misfire code has cleared. If the engine still stumbles, double‑check the coil’s seating and the electrical connector.
Common Pitfalls to Avoid
- Forgetting to disconnect the battery – this can cause accidental shorts.
- Using the wrong torque value – too loose and the coil may vibrate; too tight and it may crack.
- Neglecting dielectric grease – moisture can seep in and degrade the coil over time.
- Skipping a visual inspection of the spark plug – a fouled plug can masquerade as a coil issue.
Tips for Extending Coil Life
While ignition coils are robust, they benefit from a few care habits. Keep the engine bay clean; oil or debris on the coil can cause overheating. Periodically inspect the spark plugs and replace them as recommended—usually every 30,000 miles for the TSX. Lastly, avoid running the engine at excessively high RPMs for extended periods, as heat is the enemy of coil longevity.
Frequently Asked Questions
Can I replace the ignition coil with the engine running?
No. The engine must be off and the battery disconnected. Hot components and moving parts make the job unsafe and can damage the new coil.
How much does a replacement coil cost for a 2012 Acura TSX?
Pricing varies, but a quality OEM coil typically ranges from $70 to $120. Aftermarket options may be cheaper, though it’s wise to verify compatibility.
Do I need to replace the spark plugs when I change the coil?
It’s not mandatory, but inspecting the plugs while the coil is out is a smart move. Replacing them at the same time can prevent future misfires and ensure optimal performance.
Will a faulty coil trigger the check‑engine light?
Yes. The engine control module monitors coil performance and will set a misfire code (P0300‑P0304) if it detects irregularities, which then illuminates the check‑engine light.
