Catalytic Converter for Subaru Legacy (2015-2019) 2.5L

Emissions-Compliant Direct-Fit Catalytic Converter for 2015-2019 Subaru Legacy

What it Does: The direct-fit catalytic converter replaces the depleted factory emissions core on the 2015-2019 Subaru Legacy to restore exhaust gas scavenging, eliminate P0420 diagnostic trouble codes, and ensure federal emissions compliance.

The Stock Subaru Legacy Catalyst Deterioration

The factory catalytic converter on the BN chassis Legacy frequently suffers from washcoat depletion and substrate clogging over extended mileage. Boxer engine architectures, specifically the horizontally opposed FB25, are notorious for passing minute oil vapor through the PCV system into the exhaust stream. Over thermal duty cycles, this oil residue coats the internal ceramic monolith, causing thermal degradation of the active noble metals and elevated exhaust backpressure that hampers engine efficiency and triggers check engine lights.

The Engineering Solution

Engineered as a direct bolt-on solution, this assembly features a heavy-gauge Stainless Steel outer casing built to withstand severe thermal expansion and road debris. Internally, a high-efficiency Platinum-loaded substrate promotes rapid light-off temperatures to actively convert hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx) into harmless inert gases. Heavy-duty, precision-cut flanges eliminate exhaust leaks, while integrated factory-placement O2 sensor ports allow factory air-fuel monitoring sensors to operate without signal bias or post-cat DTC errors.

Technical Specifications

Compatibility

• 2015 Subaru Legacy 2.5i (Base, Premium, Limited) 2.5L H4
• 2016 Subaru Legacy 2.5i (Base, Premium, Limited) 2.5L H4
• 2017 Subaru Legacy 2.5i (Base, Premium, Sport, Limited) 2.5L H4
• 2018 Subaru Legacy 2.5i (Base, Premium, Sport, Limited) 2.5L H4
• 2019 Subaru Legacy 2.5i (Base, Premium, Sport, Limited) 2.5L H4

Frequently Asked Questions

Does this fit the BN Legacy?
Yes, this is a direct fit for the 2015-2019 Subaru Legacy equipped with the FB25 engine.

Will this resolve an existing P0420 catalytic efficiency code?
Yes, replacing a contaminated or failed OEM converter with this fresh substrate assembly restores chemical conversion efficiency and clears active P0420 codes.

The Subaru Precision Standard

Engineered for exact mechanical alignment, this converter matches factory hanger and flange spacing to maintain true boxer engine exhaust balance, crisp throttle response, and quiet OEM-level acoustic profiles.