Subaru Catalytic Converter Replacement Cost
Replacement of the under-car or manifold-integrated catalytic converter assembly to resolve P0420 efficiency codes.
Why this fails
Excessive oil consumption (common on FB20/FB25 engines) or coolant leaks from head gaskets (EJ25 engines) coat the precious metal substrate, "poisoning" the catalyst and preventing oxygen storage.
What the job involves
- Diagnostic scan to confirm P0420 (Catalytic Efficiency Below Threshold) and verification of Air/Fuel sensor health.
- Removal of the plastic under-tray and heat shielding.
- Extraction of upstream and downstream O2 sensors (often requiring heat/torch).
- Removal of the manifold/converter assembly from the cylinder heads (Boxer engines) or mid-pipe collection point.
- Installation of new multi-layer steel (MLS) exhaust gaskets and spring-bolt hardware.
If you delay this repair
A clogged converter increases exhaust backpressure, leading to reduced fuel economy, sluggish acceleration, and eventual engine overheating or catastrophic pre-ignition (knock).
Save money
- • Check Federal Emissions Warranty: Subaru often covers converters for 8 years/80,000 miles (15yr/150k in partial-zero emissions states like CA/NY).
- • Address oil consumption early; replacing the converter without fixing the PCV valve or piston rings will lead to a repeat failure within 12 months.
- • Use Rockstar or specialized O2 sensor sockets to avoid stripping threads on the oxygen sensors during transfer.
OEM part numbers
FAQ
How much does subaru catalytic converter replacement cost cost in 2026?
Expect $1,450–$3,400 at most US shops, parts plus labor.
How long does the job take?
1.5–3.5 labor hours typically.
Can I do this myself?
Yes — DIY difficulty 3/5.
What happens if I delay?
A clogged converter increases exhaust backpressure, leading to reduced fuel economy, sluggish acceleration, and eventual engine overheating or catastrophic pre-ignition (knock).