Ignition Coil Guide for the 2007-2015 BMW 335i (N54 & N55)
Experiencing misfires or a rough idle? This guide will help you choose the right replacement ignition coils for your 335i.
- Ignition coil failure is a very common problem on the 2007-2015 BMW 335i, causing misfires and a check engine light.
- It is highly recommended to replace all six ignition coils and spark plugs at the same time, especially on cars with over 60,000 miles.
- For best results, use OEM-equivalent brands like Bosch, Delphi, or Eldor. Delphi and Eldor are considered upgrades over the original Bosch coils found in N54 engines.
- Replacement is a simple DIY job that requires no special tools and can be completed in under an hour.
Symptoms of a Failing Ignition Coil
Ignition coil failure is a well-known issue for 2007-2015 BMW 335i owners. The turbocharged N54 and N55 engines are sensitive to ignition health, and a weak coil can cause noticeable problems. Symptoms often appear suddenly and are more obvious under hard acceleration. 🎬 Watch: How to diagnose and replace a failing ignition coil. Here’s what to look for:
- Engine Misfires: The most common symptom. You'll feel a shaking or stumbling from the engine, especially under load.
- Check Engine Light: A failing coil will almost always trigger a check engine light. You'll see codes like P0300 (random misfire) or P0301-P0306, which point to a misfire in a specific cylinder.
- Rough Idle: The engine may run unevenly or shake while stopped.
- Loss of Power: Your car will feel sluggish and hesitant during acceleration.
- Reduced Fuel Economy: When a cylinder isn't firing correctly, your fuel efficiency will suffer.
A Note on N54 vs. N55 Engines
The 2007-2015 production range covers two engines: the twin-turbo N54 (2007-2010) and the single-turbo N55 (2011-2015). While the original Bosch coils on the N54 had a reputation for a higher failure rate, BMW later began using Delphi and Eldor coils on the N55, which are considered more robust. Many owners of N54 models upgrade to the later Delphi or Eldor style coils, as they are functionally identical and often more reliable.
Choosing the Right Aftermarket Ignition Coil
When it comes to ignition coils for the 335i, you get what you pay for. Sticking with proven OE (Original Equipment) or OEM (Original Equipment Manufacturer) brands is highly recommended for reliability, especially if your car is tuned.
Tier 1: OEM / OE-Equivalent Brands
These brands are the original suppliers to BMW and offer the best quality and reliability. They are the recommended choice for most owners.
- Bosch: An original supplier for many N54 and N55 models. While early versions had some issues, modern Bosch coils are a reliable choice.
- Delphi: BMW switched to Delphi for the N55 engine to improve reliability. These are a very popular and trusted upgrade for N54 owners. Some forum users note that genuine BMW-branded Delphi coils may have different internal construction than aftermarket Delphi-branded ones.
- Eldor: Another OEM supplier for newer BMWs, Eldor coils are considered a top-tier option and an upgrade for both N54 and N55 engines, known for handling higher power levels. 🎬 See why Eldor coils are the best upgrade for N54 engines.
- NGK: Known for their spark plugs, NGK also produces high-quality ignition coils that are a trusted option.
Tier 2: Reputable Aftermarket Brands
These brands offer a good balance of price and quality, suitable for a daily driven, non-tuned vehicle.
- Standard Ignition (SMP)
- Hitachi
- Spectra
- Walker Products
Tier 3: Value Brands
These are the most budget-friendly options. While they can work to get a car running, their long-term durability and performance under stress may be questionable. They might be suitable if you are on a tight budget or preparing to sell the vehicle.
- DriveWire
- Global Parts
- True Tech
Pro Tip: Replace in Sets
If one ignition coil fails and your car has over 60,000 miles, it's wise to replace all six. The other coils have been subjected to the same heat and wear and are likely to fail soon. Replacing them all at once saves you from future headaches and repeated repairs. It is also highly recommended to replace all six spark plugs at the same time.
Known Issues, Recalls & TSBs
There are no major open safety recalls specifically for ignition coil failure on the 2007-2015 BMW 335i according to NHTSA searches. However, BMW has issued Technical Service Bulletins (TSBs) related to ignition coils.
- SIB B12 18 14: This bulletin from 2015 noted the higher failure rate of Bosch coils on some engines and instructed dealers to replace them with Delphi coils. This confirms the industry knowledge that Delphi coils are a factory-approved update.
- SIB B12 15 15: This bulletin addresses corrosion on the metal heat shield of Delphi coils on the N55 engine. It states that moisture can cause this, but it does not affect the coil's function and the part should not be replaced for corrosion alone.
Frequently Asked Questions (FAQ)
Should I replace all six ignition coils at once?
Yes, especially if your vehicle has higher mileage (over 60k miles) or if you don't know when they were last changed. Coils wear out over time, and if one has failed, others are likely to follow. Replacing them all, along with spark plugs, is a smart preventative measure.
What is the difference between N54 and N55 ignition coils?
The coils are physically interchangeable. Early N54 engines came with Bosch coils, while the later N55 engines used more reliable Delphi or Eldor coils. It is a common and recommended practice for N54 owners to upgrade to the N55-style Delphi or Eldor coils for better durability.
Do I need special tools to replace my ignition coils?
No special tools are required for the coils themselves. The job is very simple and requires minimal tools. You simply lift a tab on the electrical connector and pull the coil straight up and out of the engine. If you are also changing the spark plugs (which is recommended), you will need a special thin-walled 14mm 12-point spark plug socket.
🎬 Watch this N55 walkthrough for gapping plugs and installing Eldor coils.Can I use a cheaper brand ignition coil?
While cheaper brands can work, the ignition system on the 335i is sensitive, especially on tuned cars. OEM-equivalent brands like Bosch, Delphi, and Eldor offer proven reliability and performance that budget brands may not match. Using a low-quality coil could lead to continued misfires or premature failure.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12138616153 12137594596 12138657273
This vehicle uses a 'pencil' or 'coil-on-plug' design. No special gapping or adjustment is needed. The N54 and N55 engines use six individual ignition coils, one for each cylinder.
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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.
- BMW 335i:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Symptoms of a Failing Ignition Coil
- A Note on N54 vs. N55 Engines
- Choosing the Right Aftermarket Ignition Coil
- Tier 1: OEM / OE-Equivalent Brands
- Tier 2: Reputable Aftermarket Brands
- Tier 3: Value Brands
- Pro Tip: Replace in Sets
- Known Issues, Recalls & TSBs
- Frequently Asked Questions (FAQ)
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