A Guide to Replacing Ignition Coils on Your 2003-2014 Mazda 6
Experiencing engine misfires or a rough idle? Your ignition coils might be the problem.
- For 2014-2016 models, check if your car falls under TSB 01-014/16 for faulty original coils.
- Stick to quality aftermarket brands like NGK, Denso, or Bosch for reliability; avoid the cheapest options.
- Always replace spark plugs at the same time as ignition coils to prevent future issues.
- Replacement is easy on 4-cylinder engines but much harder for the rear bank on V6 models.
Is Your Mazda 6 Ignition Coil Failing?
When an ignition coil starts to go bad, the signs are usually obvious. Your car's computer will often detect the problem and turn on the Check Engine Light. The most common issue is an engine misfire, which can feel like a stutter or hesitation while driving. Here are the main symptoms to watch for:
- Rough Idle: The engine shakes or vibrates more than usual when you're stopped.
- Loss of Power: Your car feels sluggish and doesn't accelerate as quickly as it should.
- Check Engine Light: You'll likely see diagnostic trouble codes like P0300 (random misfire) or P0301-P0306 (misfire in a specific cylinder).
- Worse Fuel Economy: You'll notice you're filling up your gas tank more often because unburned fuel is being wasted.
- Stalling: In more severe cases, the engine may cut out completely when idling or coming to a stop.
- Backfiring: You might hear a loud pop from the exhaust, sometimes with black smoke, as unburned fuel ignites in the exhaust system.
Known Issue: Technical Service Bulletin (TSB) for 2014-2016 Models
Mazda issued a Technical Service Bulletin (TSB 01-014/16) for some 2014-2016 Mazda 6 vehicles. It notes that ignition coils made by a specific supplier, YUMEBISHI, before March 28, 2016, could fail prematurely. This can cause a rough idle, lack of power, and misfire codes (P0300-P0304). If you have one of these model years and experience these issues, it's highly likely you have the faulty original coils. The solution is to replace them with the updated part.
Choosing the Right Aftermarket Ignition Coil
You don't need to buy the most expensive coil to get your Mazda 6 running smoothly, but you should avoid the cheapest options. Owner forums are full of stories about ultra-cheap coils failing within months. Here’s a breakdown of your choices:
- Premium Brands (Recommended): Brands like NGK, Denso, Bosch, and Delphi are well-regarded and often supply parts directly to automakers. NGK is widely considered the original equipment (OEM) supplier for Mazda, making their aftermarket coils a reliable choice. These brands offer quality and durability that is similar to the original part.
- Reputable Aftermarket Brands: Companies like Standard Ignition (SMP), Hitachi, and Beck Arnley have a long history of making reliable replacement parts. They offer a good balance of price and quality. One owner noted that a Beck Arnley box contained a refurbished OEM part.
- Economy Brands: While the low price is tempting, generic, unbranded coils often use lower-quality materials that can't handle the engine's heat and vibrations, leading to premature failure. It's generally best to invest a little more for a part that will last.
Pro Tip: Replace Spark Plugs at the Same Time
Old, worn-out spark plugs can put extra strain on a new ignition coil, causing it to fail sooner. Since you already have everything apart, it's a smart and inexpensive move to replace the spark plugs when you replace the coils. Always use high-quality plugs from a brand like NGK or Denso.
Generation Differences & Installation
Replacing the coils on a 2003-2014 Mazda 6 is generally easy, especially for 4-cylinder engines.
- 4-Cylinder Engines (2.3L, 2.5L): This is a great DIY job. The coils are located directly on top of the engine under a plastic cover. You just need to remove a single 8mm bolt and an electrical connector for each coil. The whole job can be done in under an hour with basic tools.
- V6 Engines (3.0L, 3.7L): This is more complex. The front three coils are easy to access, but the rear three are buried under the intake manifold. Replacing the rear coils requires removing the manifold, which is a much bigger job. Because of the extra labor, if you have a V6 and one of the rear coils fails, it is highly recommended to replace all three rear coils and spark plugs at the same time.
| Part/Service | Estimated Cost |
|---|---|
| Single Aftermarket Ignition Coil | $18 - $120 |
| Full Set of Aftermarket Coils (4 or 6) | $70 - $650 |
| Single OEM Ignition Coil | $75 - $150 |
| Shop Labor (4-Cylinder, All Coils) | $50 - $100 |
| Shop Labor (V6, Rear Coils) | $250 - $400+ (due to intake manifold removal) |
Frequently Asked Questions
Should I replace all ignition coils at once?
While you can replace just the one that failed, it's often recommended to replace them all, especially if your car has over 80,000 miles. Ignition coils are exposed to the same heat and wear, so if one has failed, the others may not be far behind. For V6 models, it's almost mandatory to replace the full rear set if you have the intake manifold off.
Can I drive with a bad ignition coil?
You can, but it's not a good idea. Driving with a misfire for an extended period can allow unburned fuel to get into your exhaust system, which can overheat and destroy your expensive catalytic converter. It's best to get it fixed as soon as possible.
What's the difference between OEM and aftermarket coils?
OEM (Original Equipment Manufacturer) coils are what Mazda installed at the factory. High-quality aftermarket brands like NGK (who is the likely OEM supplier), Denso, and Bosch are engineered to meet or exceed OEM specifications and are excellent alternatives. Cheaper aftermarket parts may not last as long. The biggest difference is usually price and warranty.
Are there any recalls for the Mazda 6 ignition coil?
No, there are no official safety recalls for ignition coils on the 2003-2014 Mazda 6. However, Mazda did issue a Technical Service Bulletin (TSB) for 2014-2016 models with specific faulty coils from one supplier.
Helpful Videos
Technical Specifications
OEM Part Numbers: PE20-18-100A L3G2-18-100B 1F20-18-100A AJ51-18-100A
This vehicle uses a modern Coil-on-Plug (COP) ignition system. Each cylinder has its own individual ignition coil mounted directly on top of the spark plug. This design eliminates the need for spark plug wires. Part numbers vary significantly between 4-cylinder and V6 engines, as well as between generations.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Mazda 6: