A Guide to Replacing the Catalytic Converter on Your 2011-2015 Subaru Legacy
Dealing with a P0420 code or a failed emissions test? Here's what you need to know before buying a new catalytic converter.
- The P0420 code is the most common sign of failure, but you must fix underlying engine issues (like oil consumption) before replacing the converter, or the new one will fail too.
- You must verify if your vehicle requires a CARB-compliant or EPA (Federal) converter. Installing the wrong type is illegal in states like CA, CO, NY, and ME and will cause inspection failure.
- A recall (WUJ-95) was issued for 2015 Legacy models for cracks in the front exhaust pipe assembly containing the converter; check if your vehicle is affected.
- Premium aftermarket brands like MagnaFlow and Walker are often a better choice for Subarus than cheaper alternatives to avoid the check engine light from returning.
Is Your Catalytic Converter Failing?
A failing catalytic converter on your 2011-2015 Subaru Legacy will usually make itself known. The most common sign is the check engine light turning on with a P0420 "Catalyst System Efficiency Below Threshold" code. However, other symptoms can also point to a problem.
Don't Ignore a Flashing Check Engine Light!
If your check engine light is solid, you can usually continue driving, but you should get it checked soon. If the light is flashing, it signals a serious engine misfire that can quickly destroy a new catalytic converter with unburnt fuel. Pull over immediately and turn off the engine when it's safe to do so.
Why Did My Converter Fail?
Catalytic converters don't usually fail on their own. Failure is often a symptom of another problem. On this generation of Subaru Legacy, a common cause is excessive oil consumption, which can contaminate the converter. Other issues like coolant leaks, a rich fuel mixture, or engine misfires can also ruin a new converter quickly. Before you replace the converter, it is critical to diagnose and fix the root cause, or you will likely be replacing it again soon.
Known Issues for 2011-2015 Subaru Legacy
Subaru issued a voluntary recall and service campaign (WUJ-95) for some 2015-2016 Legacy 2.5L models. The front exhaust pipe, which contains the catalytic converter, could develop cracks in its flexible bellows section. This leads to an exhaust leak, a loud noise, and a failure to meet emissions standards. The fix is a complete replacement of the front exhaust pipe assembly, performed by a dealer. While this recall specifically mentions 2015 models, it's a known failure point to be aware of for the entire generation.
Choosing the Right Aftermarket Converter
When replacing your converter, you have a choice between Original Equipment Manufacturer (OEM) parts from Subaru and aftermarket parts from other brands. OEM parts are very expensive but are designed to work perfectly with your car's sensitive emissions system. Aftermarket parts are much more affordable but can be a mixed bag.
Subarus are known for being sensitive to aftermarket converters. Cheaper aftermarket units may not have enough of the precious metals needed to work effectively, causing the P0420 code to return even with a new part. For the best results with an aftermarket part, consider these tiers:
- Premium Aftermarket (e.g., MagnaFlow, Walker): These brands have a strong reputation and are often recommended by mechanics. They build direct-fit units designed to match OEM performance and often use more durable stainless steel construction. They are a good balance of cost and quality.
- Standard/Economy Aftermarket (e.g., AP Exhaust, Eastern Catalytic, Davico): These brands offer a budget-friendly solution. They can be a good choice if the car is older or if you live in an area without strict emissions testing. However, be aware that they may have a shorter lifespan and a higher chance of triggering the check engine light.
Check for CARB Compliance!
If your vehicle is registered in California, Colorado, New York, or Maine, you MUST install a CARB-compliant catalytic converter. These are more expensive because they meet stricter emissions standards. Installing a Federal/EPA-only converter in these states is illegal and will cause you to fail your emissions inspection. Always verify which type you need before buying.
Cost to Replace a 2011-2015 Subaru Legacy Catalytic Converter
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Converter | $140 - $625 |
| Shop Labor | $150 - $350 |
| Total Estimated Cost | $290 - $975 |
Note: Costs are estimates and can vary based on your location, the specific brand chosen, and your vehicle's condition (e.g., rusted bolts).
Frequently Asked Questions
Will replacing the oxygen sensors fix my P0420 code?
Sometimes, but it's less common. While a bad oxygen sensor can cause a P0420 code, the code more often correctly points to a failing catalytic converter. A good mechanic can test the sensors to see if they are the problem before you spend money on a new converter.
Why did my brand new aftermarket converter still give a P0420 code?
This is a common issue with Subarus. It can happen for two main reasons: 1) The underlying problem that destroyed the original converter (like an oil leak) was not fixed, and it has already damaged the new one. 2) The aftermarket converter is a cheaper model that doesn't have enough precious metals to satisfy Subaru's sensitive engine computer.
Do I need to weld the new converter in?
Most aftermarket converters for the 2011-2015 Legacy are "direct-fit" models. This means they are designed to bolt directly into place without any welding, using the existing flange connections. However, heavily rusted bolts and flanges can sometimes complicate the installation.
Is my converter covered under warranty?
By federal law, major emissions components like the catalytic converter are covered for 8 years or 80,000 miles. Some states and specific Subaru warranty extensions (like for the P0420 code) may offer longer coverage. If your vehicle is near this age or mileage, it's worth calling a Subaru dealer with your VIN to check for any applicable warranties or recalls before you buy a part.
Technical Specifications
OEM Part Numbers: 44620AD88A 44620AD89A
The catalytic converter for the 2011-2015 Subaru Legacy is typically a direct-fit unit integrated with the front exhaust pipe. It features a two-bolt flange at the inlet and a two-bolt flange at the outlet. The assembly includes one port for an oxygen sensor. Depending on the vehicle's original sale location, it may require a Federal (EPA) or CARB-compliant converter.
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.
- Subaru Legacy:
- 🛍️ Shop This Part
- Is Your Catalytic Converter Failing?
- Don't Ignore a Flashing Check Engine Light!
- Why Did My Converter Fail?
- Known Issues for 2011-2015 Subaru Legacy
- Choosing the Right Aftermarket Converter
- Check for CARB Compliance!
- Cost to Replace a 2011-2015 Subaru Legacy Catalytic Converter
- Frequently Asked Questions
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